Working Out in Hot Weather
Physical activity during hot weather represents great stress for the human body - running, cycling, hiking, swimming, or just physically working can be demanding for the body, but when done in hot weather, can be even very dangerous.
However, choice of proper clothing, time of the day, nutrition, hydration, etc. may allow the athlete to regularly work out during hot weather and increase strength and stamina, and burn plenty of calories.
Updated: May 29, 2022.
During physical activity, body temperature rises and one of the tasks that must be done is to keep body temperature within biological limits - therefore, we sweat.
Higher the temperature, heavier the physical activity, more clothes we have, etc. body will sweat more. More sweat means more liquid on the skin that can evaporate - water evaporation cools the body and keep the temperature at acceptable levels. This heat is also known as the heat of vaporization or heat of evaporation.
Also, heat may increase the heart rate and blood pressure - something that people with heart issues and health issues, in general, should avoid.
Note: if You plan on working out during hot weather, check your health at your doctor's office, just in check - working out can be very tasking for the body and when done during hot weather, stress can be really high. Better safe than sorry...
Sweat is a combination of water and various minerals, also known as electrolytes - mostly sodium and magnesium but other minerals as well.
The composition of sweat varies from person to person, but typically a liter of sweat contains 1.48g of chloride, 1.15g of sodium, 0.23g of potassium, 0.02g of calcium, 0.05g of magnesium, and other compounds in smaller quantities.
Fluid loss can have various effects on the human body, depending on the amount of lost liquid. These effects are individual, but generally, effects of liquid loss on the human body depending on body weight percentage lost as sweat:
- 2% loss of body weight as sweat results in impaired performances,
- 4% loss of body weight as sweat results in the declined ability of muscles to work,
- 6% loss of body weight as sweat results in total heat exhaustion,
- 8% loss of body weight as sweat results in hallucinations,
- 10% loss of body weight as sweat results in heat stroke, circulatory collapse, and death.
Capability to perform physically simply fades away as the body loses more liquid and electrolytes, up to the point where physical activity of any kind is no longer possible - this is a very dangerous level of dehydration and mineral loss that can lead to death.
High Temperatures - Hot Weather
Tolerances to high temperatures vary and it is very individual.
Slim people often tolerate higher temperatures more easily than heavier or bulkier people - this is due to a higher skin surface-to-body volume ratio.
Also, there are other factors that determine how we feel at any given temperature, like are we in the sun or in the shade, color, type of the clothes, is there any wind of any kind, type of physical activity, age, height, weight, body fat percentage, ancestry, and habits, etc.
Dry Heat vs Humid Heat
Obviously, high temperatures are hard to define. But, people often forget to mention air humidity - the amount of evaporated water in the air.
More humid the air, sweat from the skin will harder evaporate, thus reducing the cooling effect - to compensate for that, the body will sweat even more and we will lose more liquids and more minerals. This decrease even more body's capability to perform physically.
So, if You are in the position to choose between dry heat or humid heat, the dry heat can be less stressful for the body.
Skin Protection During Hot Weather
During hot and sunny days, the skin should be protected from dangerous UV light.
It is highly recommended to use protective creams with a sunblock factor of 25 or higher, especially if you are planning to be exposed to solar radiation during critical hours - between 10:00h and 16:00h. During these hours, even reflected UV radiation can cause skin burns, so be careful.
Also, proper clothing can help a lot in protecting the body from solar radiation and heat in general.
Lightweight Clothing for Hot Weather
If you are physically active during hot weather then you need some lightweight clothes. These clothes are mostly made from natural materials like cotton, but modern materials are also something to consider. Mixed materials are most often the best choice.
For activities during daylight, white and similar bright colors are recommended for decreasing the heat from the sun - dark colors absorb sunlight, and in moderate regions heat from the sun can reach up to or even more than 1 kW per square meter (93 W per square foot) - you don't need this additional heat during high temperatures.
Many people opt for short sleeve shirts during hot weather - this is a good choice for activities in shades.
But, if you are out in the open, long sleeve shirt with wide sleeves and bright colors can be surprisingly efficient in repelling sun heat from the body.
Long sleeve shirts for hot weather are made from suitable materials that provide plenty of fresh air near the skin to promote evaporation of the sweat and thus promote a cooling effect, plus they protect much more skin area than short sleeve shirts.
But, some brands also manufacture clothing for hot weather that tightly fits the athlete's body with a very special feature - wicking is important for exercise clothing because it removes the sweat from the skin and allows it to evaporate on the surface of the clothing, cooling the athlete.
Hats are not only fashion accessories during hot weather - they protect the head from direct sunlight and help in cooling the head by allowing air to pass near the skin. Wide hats are great for protecting the head, neck, and even shoulders, but they can interfere with physical activity - choose hats according to your needs.
Sunglasses are needed for eye protection, depending on individual preferences and sensitivity. When wearing sunglasses for a longer period of time, be careful when taking them off. Proper sunglasses can be very expensive, but what you pay is often what you get ...
Staying Hydrated in Hot Weather
Staying hydrated in hot weather is one of the most important things to have in mind.
When you are sweating, you need water and in very hot weather, you need plenty of it. Drinking water is important for replenishing lost water, but also for cooling the body's core.
This doesn't mean that one should drink freezing water during hot weather - on contrary, drinking too cold water can upset the stomach and can cause diarrhea and other stomach-related problems. The last thing that you need in hot weather is to increase the loss of liquid due to stomach problems.
Replenishing lost minerals is also very important. Isotonic and similar drinks with minerals like sodium, magnesium, potassium, etc prevent muscle cramps and can significantly prolong the ability of the body to perform in hot weather. There are also pills and tablets that can help in replenishing electrolytes.
In order to prolong physical activity, one may also consider taking drinks with fast carbs, BCAA, glutamine, and similar.
Water vs Isotonic Drinks
Water contains - water. Isotonic and similar drinks contain simple carbohydrates like glucose and various minerals in different proportions:
- hypotonic drinks contain water, minerals, and carbohydrates. Carbohydrate content is less than 4-5%
- isotonic drinks contain water, minerals, and carbohydrates. Carbohydrate content is around 6-8%
- hypertonic drinks contain also water, minerals, and carbohydrates. Carbohydrate content is above 8%
It is important to note that carbohydrates up to 6-8% percent in the fluid like water, don't influence the rate of absorption.
After that level, the higher the carbohydrate percentage in the fluid, the slower the rate of absorption.
So, if you are engaged in physical activity during hot weather, you need much more fluid to keep hydrated than simple carbs to keep blood sugar levels stable - take hypotonic drinks or combine them with isotonic drinks.
If you are engaged in physical activity during normal weather conditions and you are not sweating a lot, then isotonic or hypertonic drinks can be taken in order to boost energy levels.
Nonetheless, it is highly recommended to take pure water from time to time in small sips.
Protein Intake and Hot Weather
If you are engaged in some sporting event that lasts less than 2-3 hours, taking any protein in the form of solid food is not advisable.
Such food will take a relatively long time to digest and can hamper physical performance. Also, to digest protein, the body needs fluids, so during protein digestion, water absorption can be slowed down. Not so good when sweating heavily.
If you are physically active for longer periods of time and you can't have a break for a proper meal and rest (at least 45 - 60 minutes), take really small portions "on the run" of solid meals (mostly protein + carbs) with some water during the meal and have water every 10 - 15 minutes to keep your body hydrated.
Taking such meals will help you keep nitrogen (amino acids) and blood sugar levels more or less stable. If preparing and taking such meals is not practical then consider taking various Meal Replacement Powder (MRP) shakes or bars when needed.
Also, having a few tablets of BCAA, EAA or complete amino acids from time to time can help in keeping strength and stamina high.
For short - if You want to prevent catabolism and increase energy levels, go for a BCAA/Amino drink with some electrolytes and with or without simple carbs.
Rowing in Hot Weather
When rowing outside, row early in the morning or late in the evening. Be sure to have enough water and other liquids and just in case, a protein bar or Ready-to-Drink meal replacement or some protein/energy shake or anything similar -rowing exercises can last a rather long time.
Also, good multimineral and multivitamin tablets are recommended.
Some rowers consider all of this as a burden, except perhaps a bottle of water, but if you want to keep your body functioning properly during hot weather while rowing for an extended period of time, the body simply must have what it needs - water and macro- and micronutrients.
Fortunately, when rowing on the water, there is plenty of air circulation around the body, which decreases the sweating.
When rowing indoors, during summer, be sure to have the AC unit on, but stay away from a direct stream of cold air. Adjust temperature according to your preferences and enjoy your rowing workout. Just to be sure, have a bottle of water with you.
Running in Hot Weather
Running in hot weather provides plenty of air around the body - the cooling effect due to sweating is increased.
But due to running, produced energy is also much higher when compared with walking or similar activities.
Bottom line - running will significantly increase sweating and loss of water and minerals. For the running events that last a longer period of time proper hydration in the form of water and other drinks is absolutely needed in order to keep the body functioning.
Skin protection in the form of high sun block factor creams, hats, and glasses is highly advisable.
Cycling in Hot Weather
Cycling provides much more air around the body when compared with running or walking.
Energy expenditure depends on the intensity of cycling. Generally, it is much easier to take fluids and liquid food when cycling than when running - you can have food, water, and drinks with You all the time, while this is much harder when running. So, fluids and food can be taken when desired.
Protection in the form of glasses and helmets is recommended. Modern cycling suites promote sweat evaporation and keep the body cool as much as possible - the same thing happens with some running suites, but the effect of cooling is smaller due to smaller speed when running.
Hiking in Hot Weather
Hiking in nature usually lasts all day long. It is very important to have a proper wide hat to protect the head, neck, and as much shoulders as possible.
Bright-colored clothes protect the rest of the body from strong sun radiation. Hikers usually have backpacks with water, various drinks, and food. Taking fluids in regular intervals will keep the body hydrated while taking carbs and protein in various forms of food can help in providing energy for day-long activities.
Note that depending on the hiking track, hikers often can climb significant heights where sun radiation is even stronger, but air temperature can be much much lower - lower temperatures can trick hikers about sun radiation, so be very careful regarding sunburns.
Swimming in Hot Weather
Swimming is a great activity for fitness and staying fit during summer.
Body weight is supported by water and body strength is entirely used for positioning and propelling the body through the water.
When swimming, energy expenditure due to the type of physical activity is reduced, but swimming is not something that most people do on regular basis - muscles are not accustomed to prolonged swimming activities and can get tired quickly.
Anyway, when swimming, fluid loss in the form of sweat is minimal and depends on water temperature. Swimming in moderately warm water (25°C/77°F) provides adequate 'cooling' for the body and swimming can last for a longer period of time.
Swimming in the cold water (20°C/68°F or less) will not only stop sweating but when done for longer periods of time can cause body core temperature to drop. Not recommended without protective suits, although this vary significantly from individual to individual.
Swimming in the warm water (30°C/86°F or higher) can cause fluid loss in the form of sweat since water flow can't provide enough cooling- again, this is very individual. Swimming in very warm water (35°/95°F) can cause the body to overheat - be very careful.
Wearing hats and sunglasses when swimming - if your swimming style allows this and you plan to stay in the water long period of time, then it is recommendable to wear at least a hat.
Sun creams with higher sunblock factors are recommendable regardless of swimming style, especially for the face, neck, shoulders, chest, and upper back. Today, plenty of sun creams state that they are waterproof, but recommend applying a new protective layer of sun cream right after swimming ...
Long Story Short: Regardless of your physical activity during hot weather - be careful.
Keep yourself well protected from strong sun radiation, hydrate your body by drinking water and other fluids and watch out for symptoms of overheating - when this occurs, stop whatever you are doing, go into the shades, sit or lay down and cool yourself by drinking water and fluids.
Often, spraying (cold) water over exposed skin can help in cooling down - if you do this, do it slowly and gradually since a sudden drop in temperature of periphery blood can cause other severe health problems.
When engaged in extreme physical activities, it is recommended not to be alone - if something happens to you, other people can help. Also, if something happens to others, You can help them ...
