This summer in Boston has been hot. (Much like last summer, actually. Ain’t global warming grand?). Now, I haven’t really been checking the weather anywhere else, but I think it’s safe to assume that other places are experiencing some hot summer temperatures as well. In some places, it’s a dry heat. In others, it’s the kind of delightfully humid heat that we’ve got here. (Friends in the southern hemisphere, this post will be relevant in about six months).
Either way, just because it’s hot doesn’t mean people want to stop training. Dedicated circus artist-athletes are still going to classes and training hard.
Sometimes, people get to do their circus fun in an air-conditioned environment…and sometimes they don’t. Whether you’re training outside or in a space without air conditioning, chances are you’re going to be getting hotter and sweatier than you normally do. This is particularly true if you’re training in a very humid environment.
Exercising in high heat can challenge your body’s ability to regulate its temperature and maintain hydration, at the risk of pointing out the obvious, overheating and/or becoming dehydrated is not good.
The goal of this post is to provide some general guidelines for staying (relatively) cool and hydrated when you’re training in hot and humid weather.
When you’re training (and most every other time of day), it’s important for your body to regulate its temperature. (This is called thermoregulation by science-y types).
By way of providing some background knowledge, there are five ways for your body to regulate temperature. And by “regulating temperature”, we mean either gaining heat or losing heat.
Radiation. This one can go either way: the radiant heat of the sun can help to warm your body up or, when the surrounding temperature is cooler than that of your body, your body will give off radiant heat. Neither of these are particularly helpful in hot and humid weather.
Convection. If the air swirling past your body is warmer than your body, it’s gonna warm you up. If the air is cooler than your body, it will help to cool you down. This is where a nice big fan comes in handy. This is also why it’s so nice on hot days to open the fridge (or better yet, freezer) and bask in the cold air (but not so good for energy conservation, mind you).
Conduction. You can gain or lose heat by coming into contact with warmer or cooler objects. Water (the hot or cold kind) is a good example.
Evaporation. Your body can cool itself through the evaporation of sweat. The trick, of course, is that the sweat needs to be able to evaporate. When it’s particularly humid, the sweat doesn’t really evaporate from the skin very well. And that makes it harder for the body to cool itself.
However—regardless of whether your sweat evaporates, drips into a puddle on the floor or gets soaked up into your clothes as you work towards the ultimate goal—the Elvis-shaped sweat stain—it still contributes to fluid loss from your body.
Note: wearing layers when training in hot, humid weather isn’t a great idea. Light, breathable fabrics, on the other hand, are a good idea.
The kicker is that it only takes dehydration of 1% to 2% of bodyweight can begin to impact physiological function and have a negative effect on physical and mental performance.
Dehydrated circus artist-athletes may experience:
- Decreased muscle strength,
- Increased fatigue,
- Impaired concentration, and/or
- Decreased endurance.
Admittedly, you would have to weigh yourself before and then at some point during your training session to figure out if you’d lost 1% to 2% of your bodyweight. There are some more general signs and symptoms of dehydration that you can be on the lookout for:
- Thirst (yup: being thirsty is a sign you’re already dehydrated. So much for relying on thirst to tell you when to drink).
- Flushed skin
- Fatigue or apathy
- Muscle cramps or weakness
- Dark colored urine
The real take-home is that it really doesn’t take much fluid loss (thing mostly through sweating) for training in hot conditions to begin to compromise your performance.
Becoming and staying hydrated is really the key here.
Fun fact: the better conditioned you are, the more you’ll sweat because your body has become more efficient at removing heat. This is where high humidity becomes a confounding variable and hydration becomes even more important.
The good news is that, in general, with repeated exposure to hot environments, people tend to experience relatively rapid improvements (acclimation) in the body’s tolerance for heat. This adaptation process usually occurs within 9-14 days, depending upon the fitness level of the athlete.
When the weather first starts getting hot and humid, a good strategy that will help with the process of acclimation is to reduce your training volume and intensity for that first week or so.
By how much? Well, that’s for you to feel out for yourself. The key is to accept that in the long run, a week of ‘taking it easy’ will serve you well.
Effective Strategies for Staying Hydrated
24 hours prior to exercise
- begin regular water consumption
- use urine color as an indicator of hydration status:
- Hydrated: clear- to lemonade-colored urine
- Dehydrated: orange-yellow to apple juice-color (unless you are taking medication or vitamins, which will change the color of your urine)
2-3 hours prior to exercise
- consume 17-20 oz. of water or sports drink
- this is an adequate amount of fluid to achieve optimal hydration and allows sufficient time for urination
- consider a low Glycemic snack at this time to reduce insulin response
- higher levels of circulating insulin will also inhibit the body’s ability to break down fats for energy
10-20 minutes prior to exercise
- a higher glycemic carb is acceptable and may help preserve cellular glucose and hydration levels
- consume 7-10 oz of sports drink (glucose-electrolyte solution)
- consume 7-10 oz of water every 10-20 mins. (on particularly hot days or when you’re working really hard, a sports drink is a better idea)
- ideally, rehydration needs are determined by measuring the difference between pre- and post-exercise bodyweight (after urination)
- if you’ve lost 1 lb. (16 oz) during exercise, you should replace it with 19-24 oz (120%-150% of bodyweight lost)
- in the absence of a scale (or if you’re just not interested in measuring pre- and post-exercise bodyweight…which is quite understandable), a good guideline for the end of your training session on a hot and humid day is to drink another 17-20 oz of a sports drink
- the underlying rationale here is that on a particularly hot day where you’ve trained hard and sweated lots, your body will need not only water, but also electrolytes (particularly sodium and potassium) and some carbohydrate to begin replenishing muscle glycogen (the form of carbohydrate that gets stored in your muscles).
A quick note about hyponatremia (overhydration)
Yes, you can drink too much water. When this happens, you tip the scales and create a situation where the concentration of sodium in your body is too low. The best guidance I can offer on avoiding overhydration is this: if you find yourself drinking a lot of water (and that’s all going to be relative, so don’t rely on this post to do the thinking for you), consider adding a pinch of salt to your water.
And then maybe eat a banana for the potassium.
Remember, the goal is simply to match fluid intake to fluid loss (through sweat and urine).
If you’re exercising for longer than four hours, working hard and sweating like crazy, then you really should be drinking a sports drink (or similar), rather than just water because you will be losing a lot of sodium through your sweat. Water by itself doesn’t replenish electrolytes like sodium (but it will further dilute the sodium concentrations in your blood stream).
It’s taken more than few words for us to get there, but there you have it: some guidelines for staying hydrated while training in a hot summer weather. I hope you find this useful.
Oh, one more thing:
Being a little dehydrated and not performing your best is one thing, but I would be remiss if I didn’t acknowledge that the combination of high heat and humidity and intense exercise can sometimes all-too-easily lead to a heat-related illness (i.e., heat exhaustion or worse, heatstroke).
Now, it’s worth a reminder here that I am not a medical professional (I’m a strength coach) and the following does not constitute first aid training or medical advice. That being said: whether you’re a circus artist-athlete or a circus coach, you really should be aware of this stuff.
Heat exhaustion is a moderate heat-related illness characterized by the inability to sustain adequate cardiac output, resulting from strenuous physical exercise and environmental heat stress. Basically, your body is struggling to keep itself cool enough.
Symptoms usually include:
- Profound weakness and exhaustion
- Muscle cramps
- Core temperature below 104 degrees Fahrenheit (which is what makes having a thermometer in your first aid kit helpful) with excessive sweating and flushed appearance.
These are your cues to stop training (for the rest of the day…not just until you feel better), get thee to somewhere cool (and shady, if you’re outside) and drink some fluids (see below).
Heat exhaustion left untreated can easily progress to heat stroke. That would be bad.
Heatstroke is a medical emergency. Medical care must be obtained at once; a delay in treatment can be fatal.
This condition is characterized by the following:
- Very high body temperature (104 degrees Fahrenheit or greater as measured by oral thermometer)
- Sometimes, but not always, hot, dry skin, which indicates failure of the primary temperature-regulating mechanism (sweating),
- CNS dysfunction (for example, altered consciousness, seizure, coma).
Signs and Symptoms of Exertional Heat Stroke include:
- Elevated core temperature,
- Rapid and weak pulse,
- Pale or flushed skin,
- Excessive fatigue,
- Syncope (temporary loss of consciousness, ‘fainting’)
- Disturbance of vision,
- Mental confusion,
Important first aid considerations include dialing 911 and the immediate cooling of the body. Potential strategies include cold water immersion, using cold wet towels or ice packs, making sure to keep rotating new cold towels/ice pack in as the first ones warm up.
Again, none of this is to be considered complete or comprehensive medical advice. You may have noticed already that there is some overlap/similarity in symptoms from mild dehydration to heat exhaustion to heat stroke. That’s where you and your training friends need to be observant and, in my opinion, err on the side of caution. It’s important that should you encounter or experience something you suspect to be heat stroke, you (or the person involved) need to be referred to a healthcare professional immediately. Many other potentially life-threatening conditions can present as a heat illness and emphasis should be placed on proper medical diagnosis.
Ok. Good talk. ~Mike D.
National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes
Berardi, J. & Andrews, R. (2015). The Essentials of Sport and Exercise Nutrition (2nd ed.). Toronto: Precision Nutrition.
Flegel, M. (2008). Sport First Aid (4th ed.). Champaign, IL: Human Kinetics.
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