How can heat-related illnesses be prevented?
Summer hikes increase the risk of heat-related health problems. Often, such diseases are not due to the heat alone, and fluid loss also plays a very important role. It is therefore important to have enough drinks with you on long walks and hikes.
The latest study by Arizona State University found that many heat-related illnesses during summer hikes could simply be avoided if affected people took enough fluids. The results of the study were published in the English-language journal "International Journal of Environmental Research and Public Health".
Twelve participants were examined
For the study, twelve participants (seven women and five men aged 20 years) were asked to hike up a mountain on a day with moderate temperature (around 20 degrees Celsius). This was repeated on a hot day (around 40 degrees). The participants were previously asked to take as much liquid as they thought they needed. They were also asked to walk as quickly as possible, but without feeling uncomfortable.
What was examined?
Each time, the participants hiked up and down the mountain four times. Before the hike, the rest metabolism of the participants was recorded in order to assess their energy production during the hike. In addition, their weight, heart rate, core temperature and hydration status were measured before and after the hike. The drinking behavior of the participants was monitored throughout the hike.
Performance was impaired in hot weather
The researchers tried to find out exactly what is going on in the body when it reacts to heat stress. The fluid balance, the core temperature and the amount of sweat were analyzed in particular. The research group found that, compared to moderate weather conditions, the performance of hiking people in hot weather conditions is actually impaired.
Slower speed and longer heat exposure
This resulted in a slower pace during the hike, which in turn was associated with longer periods of sun and heat, increasing the risk of heat related illnesses, the team explains.
Participants often had too little fluid with them
The research group also found that most people did not take enough water with them to compensate for their fluid loss through sweating. They also observed that less fit participants were most negatively affected by the heat stress and performed worse overall than their fitter colleagues.
Using the data obtained, the researchers were able to calculate the rate of fluid loss of the participants by reducing their body weight. On average, the test subjects lost about one percent of their body weight - regardless of whether it was hot that day or not.
How was the drinking behavior of the participants?
In hot conditions, however, the sweat rate of the participants was higher and the people involved drank more, which often resulted in them consuming all of the liquid they had brought with them. The sweat rate was lower in moderate conditions, but the migrants also consumed less fluid.
Possible reasons for a drop in performance
A 1 percent loss in body weight is considered manageable and is unlikely to result in an adverse performance drop. But if people hike under hot conditions for more than 80 minutes and don't carry enough fluids with them, this can lead to greater losses in body weight, explains the research team.
How did the heat affect performance?
Overall, hot conditions compared to moderate conditions affected walking performance by eleven percent. In addition, aerobic capacity decreased by seven percent and the rate of exertion increased by 19 percent. In addition, the body had a higher core temperature at hot temperatures, the researchers report.
Longer travel times should be taken into account in the heat
On average, participants took about 20 minutes longer to hike under hot conditions than under moderate conditions, which could increase the likelihood of developing heat-related suffering exponentially, according to the research group. This should be considered by migrant people, especially if they have planned a longer hike. It is important to always carry enough liquid with you. (as)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
- Joshua D. Linsell, Emily C. Pelham, David M. Hondula, Floris C. Wardenaar: Hiking Time Trial Performance in the Heat with Real-Time Observation of Heat Strain, Hydration Status and Fluid Intake Behavior, in International Journal of Environmental Research and Public Health (published June 8, 2020), International Journal of Environmental Research and Public Health