Exercising in hot and humid weather without proper precautions can lead to performance declines and health risks, according to a Turkish physiotherapy expert.
Professor Buket Akıncı, head of the Physiotherapy and Rehabilitation Department in the Faculty of Health Sciences at Biruni University, said rising summer temperatures, humidity and air pollution can significantly affect exercise safety and performance.
In comments provided through a university statement, Akıncı noted that outdoor physical activity increases during the summer months, making environmental conditions an important factor in exercise planning.
She warned that heat and humidity can reduce performance when adequate precautions are not taken.
“Especially in hot and humid weather, exercising without sufficient precautions can lead to performance losses and health problems,” she said.
Akıncı explained that most of the energy produced during exercise is converted into heat. The body normally regulates this heat through sweating and evaporation.
However, high humidity interferes with this cooling process.
“When humidity increases, sweat evaporation becomes more difficult,” she said. “In this case, it becomes harder to lower body temperature, core temperature rises more quickly and the heart has to work harder.”
She added that endurance performance can decline significantly in hot and humid environments. Studies show that heart rate increases at the same exercise intensity and individuals perceive greater exertion, leading to reduced performance.
Without acclimatization to heat, performance losses can reach 10% to 30%, she said.
Akıncı emphasized that fluid loss is one of the most important risks during exercise in high temperatures. She noted that losing as little as 2% of body weight in fluids can negatively affect performance.
“When fluid loss increases, the body’s temperature regulation system is disrupted,” she said. “Core body temperature rises faster and aerobic performance decreases.”
She advised that body weight loss during exercise should be kept below 2%.
Akıncı also warned that air pollution becomes a greater concern during summer heat waves. She said exercise significantly increases breathing rate and the volume of air entering the lungs.
During physical activity, the amount of air inhaled per minute can be up to 10 times higher than at rest, she noted.
“This leads to greater inhalation of fine particulate matter, ozone and other pollutants,” she said. “On days when ozone levels are high, the strain on the respiratory and cardiovascular systems can increase.”
The body can adapt to heat over time, Akıncı said, noting that people who exercise regularly can achieve significant heat acclimatization within 10 to 14 days.
After this period, she said, sweating becomes more efficient, plasma volume increases and the heart is less stressed at the same exercise intensity.
However, she added that high humidity continues to limit sweat evaporation even after acclimatization, meaning its impact on performance persists.
Akıncı urged people exercising outdoors in summer to monitor not only temperature but also humidity and air quality. She recommended choosing cooler hours of the day and maintaining adequate fluid intake.
Children, older adults and individuals with chronic illnesses are particularly vulnerable to risks associated with heat, humidity and air pollution, she said.
“Physical activity is an essential part of a healthy lifestyle, but it is very important to plan exercise according to environmental conditions,” she added.
