Physical Activity in a Changing Climate: Addressing Heat and Air Pollution in Viet Nam
A Practical Education Brief for Healthcare Professionals
Vietnam Lifestyle Medicine Alliance
Version 1.0 | October 2026
Evidence reviewed through October 2026
Why this matters in Viet Nam
Regular physical activity is important for preventing and managing many chronic diseases, but the conditions in which people are active are changing. In Viet Nam, extreme heat, air pollution, traffic conditions, and unequal access to suitable public spaces can affect whether outdoor activity is safe, practical, and sustainable. This raises an important question for healthcare professionals: how can we continue to encourage physical activity while helping people reduce avoidable environmental exposure?
The issue is particularly relevant in Vietnamese cities. At a national conference in September 2026, Vietnamese government agencies, the World Health Organization, and the United Nations Development Programme highlighted the continuing health burden of air pollution and the need to translate national commitments into effective action. [4] A study published in July 2026, using meteorological observations from 1981 to 2022 and satellite data, also examined extreme heat and urban heat island patterns in Ha Noi and Ho Chi Minh City. The study identified changes in heat-related indicators and an expansion of areas with elevated land surface temperatures, although the findings differed between the two cities and depended partly on the indicators and definitions used. Land surface temperature is not the same as air temperature or an individual's heat exposure, but the findings offer useful evidence of changing urban thermal environments. [5]
These conditions can make familiar health recommendations difficult to follow. Someone may understand the benefits of walking regularly but live beside a busy road, work long hours outdoors, or have limited access to a cooler place for exercise. The recommendation itself may be scientifically sound, yet difficult to implement because of circumstances largely beyond the person's control.
This Education Brief examines one practical connection between Lifestyle Medicine and Planetary Health: how to preserve the benefits of physical activity while taking heat, air quality, individual vulnerability, and everyday living conditions into account.
The benefits of physical activity remain important
Physical activity has well-established benefits for cardiovascular, metabolic, musculoskeletal, and mental health. It supports physical function, improves quality of life, and contributes to the prevention and management of many noncommunicable diseases. The World Health Organization recommends regular aerobic and muscle-strengthening activities, emphasizing that some physical activity is better than none and that participation should reflect a person's abilities and health circumstances. [1]
Environmental risks do not remove these benefits. However, outdoor activity can increase physiological heat strain and the amount of polluted air inhaled, particularly during prolonged or vigorous exertion. Healthcare professionals therefore need to consider both the benefits of movement and the conditions in which it occurs, rather than treating outdoor exercise as either consistently safe or necessarily harmful.
The World Health Organization's 2024 evidence summary on air pollution and personal interventions generally supports maintaining regular physical activity, even when local air quality is not optimal. Evidence from observational studies and modeling suggests that the longer-term benefits of physical activity often outweigh air-pollution-related risks in many circumstances, particularly among healthy adults in high-income countries. However, the evidence is less certain for susceptible populations, indoor environments, and low- and middle-income countries. These findings should not be interpreted as establishing that every outdoor activity is appropriate during severe pollution episodes. [2]
The objective is not to replace physical activity with inactivity. It is to help people remain active while reducing avoidable exposure when environmental conditions or individual health circumstances make this necessary. During major pollution episodes, public-health advisories may recommend limiting strenuous outdoor activity, particularly for people at greater risk. Such advice should be considered alongside individual health needs and the available alternatives.
1. Understanding heat-related risks during physical activity
During physical activity, the body produces additional heat and must dissipate it to maintain a safe internal temperature. High air temperature, humidity, direct sunlight, limited airflow, clothing, and exercise intensity can make this process more difficult. In hot and humid conditions, sweat evaporation becomes less effective, increasing physiological strain.
Heat exposure can contribute to dehydration, heat exhaustion, and other heat-related illnesses. In severe circumstances, exertional heatstroke may occur and requires emergency medical care. The World Health Organization also recognizes that heat stress can worsen underlying conditions, including cardiovascular, respiratory, renal, and metabolic diseases. [3]
Heat-related risk cannot be determined from air temperature alone. Humidity, duration of exposure, exercise intensity, access to shade and cooling, heat acclimatization, underlying health conditions, and certain medications may influence an individual's response. Someone accustomed to a hot climate is not necessarily protected during unusually intense or prolonged heat exposure, particularly when illness, dehydration, inadequate recovery, or other vulnerabilities are present.
This matters in Viet Nam because hot and humid conditions can affect everyday activity even outside officially declared heatwaves. Someone who works outdoors may already experience considerable physical strain before beginning recreational exercise. An older person living in poorly cooled housing may have fewer opportunities to recover from daytime heat, particularly when nighttime temperatures remain high.
When discussing physical activity, healthcare professionals should consider heat exposure as a potentially important health factor rather than simply a matter of comfort or personal preference. What matters is not only whether someone is willing to exercise, but also whether the activity and surrounding conditions are appropriate for that person's circumstances.
2. Understanding air pollution-related risks during physical activity
Outdoor air pollution includes several pollutants with established health effects. Fine particulate matter, particularly particles with an aerodynamic diameter of 2.5 micrometers or smaller (PM2.5), and ground-level ozone are especially relevant when considering outdoor physical activity. Exposure to fine particles is associated with adverse cardiovascular and respiratory outcomes, while ozone can irritate the respiratory system and affect lung function. [7]
During exercise, breathing generally becomes faster and deeper, increasing the potential amount of polluted air inhaled. The inhaled dose depends on pollutant concentration, breathing rate, activity duration, and the environment in which exercise takes place.
These considerations do not mean that outdoor activity should routinely be discouraged. The type and intensity of activity, local pollution conditions, individual vulnerability, and availability of lower-exposure alternatives all help determine what may be appropriate.
A 2026 article published in CHEST proposed a practical approach to counseling patients about outdoor exercise during air-pollution episodes. The authors emphasized individual cardiopulmonary vulnerability, locally available air-quality information, and possible adjustments to activity timing, location, intensity, and duration. Importantly, the article appeared in the journal's How I Do It section and described an approach based on the United States Air Quality Index. It did not establish a validated clinical decision algorithm for Viet Nam, and its numerical thresholds should not be transferred directly into Vietnamese practice without appropriate evaluation and adaptation. [6]
A short walk and a prolonged high-intensity training session involve different exposure circumstances. Similarly, a healthy recreational runner, a person with stable cardiovascular disease, and someone experiencing poorly controlled respiratory symptoms may require different considerations. Environmental information can help inform these discussions, but it cannot replace individualized clinical assessment when that assessment is needed.
3. Interpreting air-quality and heat information in Viet Nam
Air-quality information can help people understand changing environmental conditions, but it needs to be interpreted carefully. An Air Quality Index summarizes selected pollutant measurements to communicate air conditions and associated health concerns. It is not a direct measurement of the amount of pollution inhaled by an individual, nor is it a validated clinical measure of personal risk.
Viet Nam uses its own Air Quality Index system, known as VN_AQI. Technical guidance issued under Decision No. 1459/QĐ-TCMT in November 2019 established a method for calculating and communicating the index using monitoring data, including measurements of particulate matter, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. [8]
Air Quality Index systems are not standardized internationally. Different countries may use different pollutants, averaging periods, calculation methods, and category thresholds. Consequently, a numerical value reported under the United States Air Quality Index should not automatically be treated as equivalent to the same value under VN_AQI. The World Health Organization has highlighted this limitation, particularly when air-quality information is used to support decisions about reducing exposure. [2]
When reviewing air-quality information, healthcare professionals should consider the data source, monitoring location, measurement period, and whether the information is current. It is also useful to understand which pollutant contributes most to the reported conditions. Official environmental monitoring information and public-health advisories should be prioritized where available. Consumer applications and low-cost sensors may offer additional local information, but their accuracy, calibration, and interpretation can vary.
Temperature information requires similar care. A weather forecast or heat warning may be useful, but a single temperature reading does not fully describe the physiological demands associated with activity in humid conditions, direct sunlight, or poorly ventilated environments. The conditions experienced at a particular location may also differ considerably from those recorded at a weather station.
The purpose of considering these information sources is not to establish a new environmental risk score. It is to help healthcare professionals understand what environmental information can tell them, what it cannot tell them, and when additional clinical assessment or public-health guidance may be needed.
4. When heat and air pollution occur together
Heat and air pollution may occur at the same time, but their relationship is complex. Hot and sunny conditions can contribute to ground-level ozone formation, while particular atmospheric conditions may allow pollutants to accumulate. Fine particulate pollution can also vary with traffic, industrial activity, combustion sources, regional transport, rainfall, and atmospheric stability.
It is important to distinguish air pollution from climate change. Air pollution has multiple local and regional sources and should not be understood simply as a consequence of global warming. Nevertheless, climate and weather conditions can influence pollutant formation, movement, and exposure. Some interventions, including cleaner transportation and energy systems, may help reduce both air pollution and greenhouse gas emissions.
The World Health Organization recognizes that heatwaves may coincide with hazardous air-pollution episodes, creating additional challenges for health protection. [3] However, the health implications of simultaneous exposure cannot be predicted simply by adding together two separate estimates of risk. The pollutants involved, severity and duration of exposure, individual susceptibility, and available evidence all matter.
This complexity becomes relevant when considering the timing of outdoor activity. Moving an exercise session to an earlier or later hour may reduce heat exposure, but it does not necessarily guarantee cleaner air. Fine particulate pollution may be elevated during some morning conditions, while ozone concentrations can rise later in the day when sunlight and atmospheric conditions favor its formation. Local monitoring information and forecasts are therefore more useful than assuming that one particular time of day is consistently safest.
Decisions about outdoor activity may involve several changing conditions at once. No single environmental indicator can fully determine whether a particular activity is appropriate for a particular person.
5. Maintaining physical activity while reducing avoidable exposure
When environmental conditions are unfavorable, a useful starting point is to consider whether the planned activity remains appropriate and whether practical adjustments could reduce exposure without unnecessarily interrupting regular movement.
Depending on the person's circumstances, possible considerations include changing the timing, location, duration, or intensity of activity, using shaded spaces or routes with less traffic exposure, and considering suitable indoor alternatives. These are options for discussion rather than universal recommendations. Their suitability depends on the individual, the available environment, and relevant clinical or public-health guidance.
Moving indoors can reduce some exposures, but an indoor environment is not automatically safe. Indoor air quality depends on outdoor pollutant infiltration, ventilation, smoking, cooking and other indoor pollution sources, building conditions, and the effectiveness of air-cleaning measures. An indoor space without adequate cooling or airflow may also remain unsuitable during extreme heat. [2]
Personal protective measures have limitations. Some measures may reduce exposure to airborne particles but do not necessarily protect against gaseous pollutants or heat stress. Their use during physical exertion may also raise practical concerns related to fit, tolerability, and individual medical circumstances. They should not be presented as substitutes for cleaner environments, effective public-health protections, or appropriate clinical assessment.
People living with cardiovascular or respiratory conditions, or taking medications that may affect fluid balance or temperature regulation, may require individualized advice from qualified healthcare professionals. General educational messages should not be used to determine medication adjustments or exercise intensity for a particular patient.
Symptoms also matter. Chest pain, severe or unusual breathlessness, fainting, confusion, collapse, or suspected serious heat illness during activity require stopping exertion and seeking appropriate urgent medical assessment or emergency care.
The aim is to preserve the benefits of physical activity while recognizing when environmental conditions, symptoms, or individual vulnerabilities require a change in approach.
6. Health equity and the ability to stay active
Environmental conditions do not affect everyone equally. Some people have access to shaded parks, safer walking routes, suitable indoor facilities, and flexible schedules. Others live close to busy roads, work outdoors, have limited financial resources, or cannot easily change when and where they are active.
An older person may depend on nearby public spaces, accessible transportation, and family support to maintain regular movement. A construction worker, delivery rider, or agricultural worker may experience substantial heat exposure during working hours and have limited control over rest periods or access to cooling. The World Health Organization and World Meteorological Organization have emphasized that effective workplace heat protection requires attention to occupational conditions, employer responsibilities, and broader public-health measures. [9]
These circumstances matter when translating evidence into advice. A recommendation that assumes everyone can exercise in an air-conditioned facility, purchase specialized equipment, or freely change working hours may be unrealistic. It may also unintentionally disadvantage people who already face greater environmental and health risks.
For healthcare professionals, this means distinguishing between what is beneficial in principle and what is achievable in everyday life. A person's ability to maintain physical activity may depend as much on working conditions, income, mobility, and the surrounding environment as on personal motivation. Recognizing these barriers is important, but addressing them may require more than individual counseling. It may also require changes in workplaces, neighborhoods, community services, and public infrastructure.
7. Illustrative situations from Viet Nam
The following situations are hypothetical and intended to support professional discussion. They are not actual patient cases, validated management pathways, or recommendations for specific individuals.
An older adult walking regularly in Ha Noi. An older person living with hypertension has developed a regular morning walking routine. During a period of poor air quality, the person becomes concerned about the possible effects of continuing outdoor activity. Rather than responding with an automatic instruction to stop walking or relying on a single numerical index, a healthcare professional would need to consider the person's current health status, symptoms, usual activity, locally available air-quality information, and realistic alternatives. The discussion may involve whether the routine could be maintained with less exposure, whether adjustments might be appropriate, or whether further clinical assessment is needed. The objective is to preserve the benefits of regular movement without overlooking individual vulnerability.
A working adult experiencing heat exposure in Ho Chi Minh City. A working adult wishes to improve physical fitness but spends long hours commuting and has limited time for recreational activity. Hot and humid conditions make outdoor exercise difficult, particularly after a physically demanding working day. Simply advising the person to exercise more may fail to account for fatigue, occupational heat exposure, recovery, and access to suitable environments. A more useful discussion would consider the person's existing physical demands, health status, goals, and available opportunities for movement. Occupational physical activity and planned exercise may have different characteristics, and additional exercise should not be considered independently of the person's total workload and recovery needs.
Neither situation has one universally appropriate solution. Both illustrate why environmental information, individual circumstances, professional judgment, and shared decision-making need to be considered together.
8. Five considerations for professional discussion
Environmentally informed conversations about physical activity can begin with five considerations.
The person's health and activity context comes first. Current activity, underlying health conditions, symptoms, functional capacity, occupational demands, and the purpose of the planned activity may help determine whether general educational advice is sufficient or individualized clinical assessment is needed.
Environmental conditions should then be considered. Heat, humidity, air quality, activity timing, location, and the reliability of available environmental information can influence exposure. Conditions may change considerably within the same city and over the course of a day.
Practical alternatives may also be relevant. Where appropriate, changes to timing, location, activity type, intensity, or duration may help maintain movement while reducing avoidable exposure. These adjustments should remain consistent with the individual's health circumstances and applicable clinical guidance.
Feasibility and equity are equally important. Income, working hours, disability, mobility, caregiving responsibilities, access to suitable spaces, and recovery needs may determine whether an otherwise reasonable recommendation can be followed.
Finally, the need for action beyond the individual should be recognized. Healthcare organizations, employers, schools, communities, urban planners, and environmental authorities may have roles in creating conditions that make physical activity safer and more accessible.
These considerations are intended for professional education and reflection. They do not constitute a validated risk-assessment instrument, a clinical decision algorithm, or a substitute for individualized assessment.
9. From individual choices to supportive environments
Individual decisions remain important, but they cannot eliminate many of the environmental conditions that influence physical activity. Safer walking and cycling routes, accessible public spaces, urban shade, cleaner transportation, improved air quality, and appropriate workplace protections can help create more favorable conditions for movement. Some of these measures may also provide broader health and environmental benefits when they reduce emissions, support active transportation, or improve urban environments.
Healthcare organizations can contribute by recognizing environmental barriers during health education, supporting access to suitable activity options where feasible, and working with other sectors when problems extend beyond individual clinical care. Schools, workplaces, and community organizations can also help create environments that support movement while reducing avoidable heat and pollution exposure.
This does not require healthcare professionals to become environmental regulators or urban planners. It means recognizing that the success of Lifestyle Medicine interventions may depend partly on decisions made outside the healthcare system. Cleaner air, accessible spaces for movement, and safer working environments are not simply matters of individual preference; they are conditions that can support or constrain health.
For Viet Nam, stronger collaboration between healthcare, public health, environmental monitoring, occupational health, education, and urban planning could help connect individual health goals with the conditions needed to achieve them.
10. Implications for professional education in Viet Nam
Viet Nam's current legal and professional framework provides a relevant foundation for this discussion. The Law on Disease Prevention No. 114/2025/QH15 and Decree No. 165/2026/NĐ-CP took effect on July 1, 2026. The Ministry of Health also issued Decision No. 1983/QĐ-BYT on July 1, 2026, providing guidance on controlling risk factors and supporting people with risk factors or noncommunicable diseases in community settings. This guidance addresses the assessment of physical activity, identification of barriers, goal setting, follow-up, and counseling related to environmental pollution exposure. [10–12]
These developments reinforce the importance of prevention, risk-factor management, and health education. International evidence concerning heat, air pollution, and physical activity can support professional learning, but its application still needs to be considered within the Vietnamese healthcare context. Healthcare professionals should understand the strengths and limitations of environmental information and recognize when a situation requires additional clinical assessment or referral.
It is equally important to distinguish general health education from professional activities such as diagnosis, treatment, rehabilitation, and individualized therapeutic exercise prescription. An Education Brief developed by VLMA does not establish a new professional qualification, authorize clinical practice, or replace standards and guidance issued by competent Vietnamese authorities. Healthcare professionals must continue to work within their legally authorized scope of practice and follow applicable clinical and institutional requirements.
The value of this resource lies in strengthening environmental awareness and evidence-informed professional discussion, not in creating another set of clinical rules.
Moving from environmental awareness to practical education
Physical activity remains an important component of Lifestyle Medicine, even as climate-related and environmental conditions change. The challenge is to preserve its benefits while recognizing that outdoor activity can involve risks that vary according to place, time, intensity, and individual circumstances.
For the Vietnam Lifestyle Medicine Alliance (VLMA), this second Planetary Health Education Brief builds on Planetary Health and Lifestyle Medicine in Viet Nam. While the first brief introduced the broader relationships between Lifestyle Medicine, environmental systems, and human health, this resource examines one issue in greater depth: how heat and air pollution can influence the safety, feasibility, and accessibility of physical activity.
The purpose is not to create a new clinical guideline or transfer environmental responsibility onto individuals. It is to encourage the appropriate use of scientific evidence, careful interpretation of environmental information, and greater attention to the circumstances in which physical activity recommendations are implemented.
For healthcare professionals in Viet Nam, the opportunity is to connect what is already known about the benefits of physical activity with a better understanding of the environments in which people are expected to remain active. Good advice matters, but so do the conditions that make it possible for people to follow that advice.
References & Further Learning
[1] World Health Organization. WHO Guidelines on Physical Activity and Sedentary Behaviour. Geneva: World Health Organization; 2020.
[2] World Health Organization. Air Pollution: Personal Interventions and Risk Communication. Questions and Answers. October 4, 2024.
[3] World Health Organization. Heat and Health. Updated July 31, 2026.
[4] World Health Organization Viet Nam. Viet Nam's Second National Air Pollution Conference to Focus on Turning Policy Commitments into Clearer Air. September 29, 2026.
[5] Nga PTT, Mau ND, Duong TH, Thuy TT. Urban Heat Intensification and Heatwave Trends in Hanoi and Ho Chi Minh City, Vietnam. Advances in Meteorology. 2026;2026:9049157. doi:10.1155/adme/9049157.
[6] Glick M, Bosma C, Monoson A, Callahan S, Huang Y-CT, Balakrishnan B. Counseling Patients About Outdoor Exercise During Air Pollution Events. CHEST. Published online June 18, 2026. doi:10.1016/j.chest.2026.06.009.
[7] World Health Organization. WHO Global Air Quality Guidelines: Particulate Matter (PM2.5 and PM10), Ozone, Nitrogen Dioxide, Sulfur Dioxide and Carbon Monoxide. Geneva: World Health Organization; 2021.
[8] Vietnam Environment Administration. Decision No. 1459/QĐ-TCMT, dated November 12, 2019, issuing Technical Guidance on Calculation and Publication of the Viet Nam Air Quality Index (VN_AQI). 2019.
[9] World Health Organization and World Meteorological Organization. Climate Change and Workplace Heat Stress: Technical Report and Guidance. August 22, 2025.
[10] National Assembly of Viet Nam. Law on Disease Prevention No. 114/2025/QH15. December 10, 2025. Effective July 1, 2026.
[11] Government of Viet Nam. Decree No. 165/2026/NĐ-CP: Detailing and Guiding the Implementation of Selected Provisions of the Law on Disease Prevention. May 15, 2026. Effective July 1, 2026.
[12] Ministry of Health of Viet Nam. Decision No. 1983/QĐ-BYT, dated July 1, 2026, issuing Guidance on the Control of Risk Factors, People with Risk Factors, and People Living with Noncommunicable Diseases in the Community.
About this Education Brief
This resource is part of the VLMA Knowledge & Evidence initiative and is intended to support evidence-informed learning and professional discussion among healthcare professionals in Viet Nam.
Suggested citation: Vietnam Lifestyle Medicine Alliance. Physical Activity in a Changing Climate: Addressing Heat and Air Pollution in Viet Nam. VLMA Planetary Health Education Brief No. 2. Version 1.0. October 2026.
Educational disclaimer: This resource is intended for educational purposes only. It does not constitute medical advice, a clinical practice guideline, a validated risk-assessment tool, a standard of care, or an accredited continuing medical education activity. It is not a substitute for individualized professional assessment, applicable public-health advisories, or relevant clinical and occupational safety guidance. Healthcare professionals should follow applicable Vietnamese laws and regulations, their legally authorized scope of practice, professional standards, institutional policies, and relevant clinical guidance when providing care.
Planetary Health Alliance affiliation: Vietnam Lifestyle Medicine Alliance is a Member Organization of the Planetary Health Alliance. This Education Brief was developed independently by VLMA and is not a Planetary Health Alliance publication or an endorsement by the Alliance.
Statement about represented views: The views, opinions, and information expressed in this publication are those of the author(s) and do not necessarily represent the official policy, position, or views of the Planetary Health Alliance.
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