Hydration and Heat Safety for Athletes

By 4Football Staff · October 3, 2026 · 10 min read

How much to drink, what the signs of dehydration and heat illness are, why football equipment raises the risk, and what coaches and parents should do when something goes wrong.

It is a humid August afternoon, the first week of practice, and a lineman in full pads is on his fourth set of drills. He feels a little off but does not want to be the one who sits out. A teammate notices he has stopped sweating as much and is stumbling. In a program with a plan, a trainer is already walking over. In a program without one, the next few minutes decide whether this becomes a story about a scare or a tragedy.

Heat illness is one of the most preventable serious dangers in football, and good hydration is part of the answer. This guide explains how fluids work for athletes, how heat illness develops, what to do when it happens, and which rules and habits reduce the risk. It is general education and does not replace a team's medical staff, an emergency plan or a doctor's advice.

Why football carries heat risk

Football combines several features that make hot weather riskier than in many sports.

• Equipment. Helmets, shoulder pads and other gear trap heat and make it harder for sweat to evaporate, which is the body's main way of cooling off. In the early days of camp, when full pads may be restricted by rule, risk is already high.
• Timing. Preseason practice often falls in the hottest weeks of the year, and some athletes arrive out of shape or after weeks of little training in the heat.
• Intensity and duration. Repeated bursts of effort, long practices and sometimes two sessions a day produce a lot of body heat.
• Body size. Larger athletes, particularly linemen, have a lower ratio of surface area to mass and so shed heat less easily. This is a major reason that big players are overrepresented in heat-illness reports.
• Poor starting hydration. Players who arrive thirsty, sleep-deprived or ill carry their risk into the practice field.

How the body handles heat

During exercise, muscles turn only part of the energy they use into movement, and the rest becomes heat. The body cools itself mostly by sweating. Sweat cools you only when it evaporates, so high humidity, heavy gear and still air all slow the process. Blood is diverted to the skin to carry heat away, which means less is available for the muscles and the gut. Eventually, if heat builds faster than it can be shed, the core temperature rises, and organs begin to suffer.

Sweat also carries sodium and other electrolytes. Sweat rates and sodium concentrations vary widely from person to person. Some athletes lose a visible white salt crust on clothes; others hardly any. There is no single "right" amount of fluid for everyone.

How much should you drink?

There is no magic number, but there are practical principles.

Before activity

Start well hydrated. Drink fluids regularly through the day, not only in the hour before practice. A pale-yellow urine color, similar to light lemonade, is a rough sign of good hydration in most healthy people, while dark amber suggests you need more fluid. (Some vitamins and medicines change urine color, so use this as a guide, not a test.) A common recommendation is to drink a good amount of fluid in the couple of hours before activity and some more shortly before.

During activity

Drink to replace what is being lost, without overdoing it. Many athletes sweat more than they drink. A commonly cited concern in sports medicine is losing more than about two percent of body weight during exercise, which can reduce performance and add strain. Because needs differ, many teams use scheduled water breaks, which also serve as rest breaks, and let players drink as thirst and the schedule require. Having cool, flavored or plain water available makes people drink more.

After activity

Replace what you lost. A simple method is to weigh yourself (in similar clothing) before and after practice. A rule of thumb is that each pound lost is roughly 16 ounces of fluid, and many guidelines suggest drinking somewhat more than was lost to account for continued sweating and urine. Eating a meal with some salt helps hold on to the fluid. Chocolate milk, soup, fruit and sports drinks can all help.

Water, sports drinks and everything else

For most workouts under an hour, water does the job. Sports drinks, with carbohydrate and sodium, can help during longer or harder sessions, in heavy sweaters, and when sessions are close together. They are not magic, and sugary drinks consumed all day in addition to a normal diet add unneeded calories.

• Energy drinks. These contain high levels of caffeine and sometimes other stimulants. Health organizations generally advise against them for children and adolescents. Caffeine can also increase heart rate and, in large amounts, interact with heat stress.
• Sodas and juice. They can work for calories but are poor choices for primary hydration.
• Electrolyte tablets and powders. Useful for some heavy sweaters; a doctor or dietitian can advise.
• Salt. Salty foods around meals usually cover sodium needs for most players, but athletes with medical conditions should ask their doctor before changing their salt intake.

Can you drink too much?

Yes. Exercise-associated hyponatremia is a dangerous drop in blood sodium that can follow drinking large volumes of plain water, particularly in long events. It is rare in football but has been reported. This is one reason health professionals advise drinking in line with thirst and sweat loss rather than forcing large amounts. Symptoms can resemble heat illness (headache, nausea, confusion), so medical staff need to assess a sick athlete rather than assuming.

A hypothetical hot practice, step by step

Imagine a team practicing on a hot, humid morning in the second week of camp. A well-run program might look like this, although every program and state has its own rules.

1. Before practice. Players arrive having eaten breakfast and drunk water. The trainer checks the heat reading and the plan says that above a certain value, helmets-only and extra breaks apply.
2. Warm-up. Coaches keep the early work lighter and in the shade where possible.
3. Water breaks. Players take scheduled breaks, rotating through water stations, with extra breaks as the heat builds. Shade or fans are available, and ice towels sit ready.
4. Observation. Staff watch for players who slow down, stumble, stop sweating normally or seem confused. A player who tells a coach he feels dizzy is sent to the trainer, not told to run it off.
5. After practice. Players weigh in, eat and drink. A coach may check on anyone who lost a lot of weight.
6. Next morning. The plan adjusts based on how the team looked and what the forecast says.

None of this is complicated. The difference between a safe practice and a dangerous one is often simply that somebody was paying attention and had the authority to change the plan.

Heat illness: a spectrum

Heat illness ranges from uncomfortable to deadly. Learning the stages helps coaches and parents recognize trouble.

Heat cramps

Painful muscle spasms, often in the calves, hamstrings or abdomen, in someone who has been sweating heavily. Rest, cooling, fluids and gentle stretching often help. Cramps can be a warning that the athlete is struggling with heat.

Heat exhaustion

Heavy sweating, fatigue, weakness, dizziness, headache, nausea, vomiting, a fast heartbeat, and sometimes fainting. The athlete is still aware and the core temperature, while elevated, is below the heat-stroke range. The athlete should stop, move to a cool place, remove excess gear, drink fluids if able, and be cooled and watched. If symptoms are significant or do not improve rapidly, medical care is needed. Heat exhaustion can progress to heat stroke.

Exertional heat stroke

The most serious form and a medical emergency. It is typically defined by a high core body temperature (roughly 104 degrees Fahrenheit or higher) together with central nervous system changes such as confusion, irritability, slurred speech, collapse, seizures or unresponsiveness. Sweating may or may not be present; the absence of sweat is not a requirement. Heat stroke can happen to a fit athlete, including early in a workout.

The key to survival is speed: the sooner the body is cooled, the better the outcome.

What to do if you suspect heat stroke

Athletic trainers and sports-medicine organizations stress a "cool first, transport second" approach.

1. Call emergency services (911 in the United States) right away.
2. Begin cooling immediately. The most effective method is immersion in a tub of cold water, with the aim of lowering the core temperature quickly. If a tub is unavailable, use cold, wet towels or ice, apply them to as much of the body as possible, and keep rotating them.
3. Remove equipment and excess clothing.
4. Do not delay cooling to wait for the ambulance.
5. Stay with the athlete and monitor breathing and responsiveness, following your first-aid training.
6. Do not give fluids by mouth to someone who is confused or unresponsive.

Teams should have a written emergency action plan that names who does what, where cold tubs and equipment are, and how an ambulance reaches the field. Our guide to emergency action plans for football teams covers this in detail. Core temperature is measured accurately with a rectal thermometer, which is why trained medical staff are important; mouth, ear and forehead readings are unreliable in this setting.

Acclimatization: the best prevention

The body adapts to heat over about one to two weeks of gradually increased exposure. Adaptations include sweating earlier and more efficiently, lower heart rate for the same work and a better ability to hold sodium. This is why most serious cases happen in the first days of practice.

Governing bodies have responded with acclimatization rules. The details differ by level and state: schedules often phase in the amount of time, the equipment (helmets only, then helmets and shoulder pads, then full pads), and the number of practices per day over the first days of preseason. Many states use guidelines from their state association, and the NCAA has its own rules for college football. We do not list specifics because they change and differ. Confirm the current rules with your state association or athletic department, and see the high school directory to find the programs near you. Fans can also keep an eye on the schedule for early-season games played in hot weather, and the injury report for pro players listed as out, although it will rarely say why.

Heat measures: beyond the air temperature

The temperature on a phone does not tell the whole story. Humidity, sun and wind matter. Many programs use a wet bulb globe temperature (WBGT) reading, which combines air temperature, humidity, solar radiation and wind into one value. Policies then set limits, such as extra rest, removing equipment or canceling practice when WBGT crosses certain thresholds. The thresholds differ by organization and state, so check your own.

Practical steps programs use when the heat index is high include:

• Shift practices to early morning or evening.
• Shorten sessions and cut the total contact or conditioning.
• Add more frequent, longer water breaks in the shade.
• Reduce equipment (helmets only, or shorts and shells).
• Provide ice towels, cooling stations and cold tubs.
• Monitor players more closely, especially those at greater risk.

Who is at greater risk?

Several factors raise an athlete's risk on a given day.

• Early in the preseason, before adaptation.
• Poor fitness or sudden, intense conditioning.
• Higher body weight or body fat.
• A recent illness, fever, vomiting or diarrhea.
• Poor sleep.
• Certain medications and stimulants (ask a doctor).
• A past episode of heat illness.
• Sickle cell trait, which carries specific risks during intense exertion and is addressed by many programs through screening and precautions.

Athletes should tell a coach or trainer if they feel unwell. Coaches should create a culture where saying "I don't feel right" is respected, not mocked.

Practical habits for athletes and parents

1. Drink throughout the day, not only at practice.
2. Eat regular meals with some salt; see Nutrition for Football Players.
3. Sleep enough. Our guide to sleep and recovery explains why this matters.
4. Wear light, moisture-wicking clothing under gear.
5. Know the signs of heat illness and speak up early.
6. Weigh in before and after practice if your team does it, and report big losses.
7. Do not train hard in the heat when sick.
8. Ask the coach about the heat plan, water access and the emergency plan.

For summer workouts outside team time, see Training in the Summer Heat Safely.

Cold, too

The reverse problem exists in late-season games. Wet, cold, windy conditions can lead to hypothermia, although it is less common in football. Dry layers, hats and gloves, warm fluids and getting wet clothing off are standard. Players who stand on a sideline for long periods are more at risk than those playing.

Return after heat illness

An athlete who has had heat exhaustion or heat stroke should not simply go back to practice. Return should follow a doctor's clearance and a gradual plan guided by the medical staff. The timing is individual. Pushing back too early can cause a repeat.

The short version

• Football gear, big bodies and August practices raise heat risk.
• Start hydrated, drink steadily, and rehydrate after practice with fluids and food.
• Water is enough for most workouts; avoid energy drinks, and do not force down huge amounts of plain water.
• Heat illness ranges from cramps to exertional heat stroke, a life-threatening emergency.
• If heat stroke is suspected, call emergency services and start cold-water cooling at once.
• Acclimatization rules exist because gradual exposure works; confirm yours with your state association or athletic department.
• Every team needs a written emergency action plan and a culture where players report feeling unwell.