Does Sweating More Mean You’re More Fit? Detailed Guide

The short answer to your question, assuming that the environmental conditions have been roughly constant, is yes.

Improving fitness impacts the way your body works in a wide variety of ways.

And your sweat response to exercise changes as you become more fit because you’re increasing the workload your body has to be able to handle.

Sweat is one of your body’s primary means of preventing your core temperature from rising to dangerous levels.

During exercise, the majority of the calories you burn actually generate heat instead of powering forward motion (sorry, but that’s just the way it is).

In fact, on the bike you are only about 20-25% efficient, meaning 75% of the energy you produce becomes heat.

That heat has to be dissipated, so your body dilates blood vessels near the skin to carry some of that heat away from your core to areas where cooler air flowing over the skin can carry away some of the heat.

Sweat makes the cooling process work even better, because as sweat evaporates off your skin it takes a lot of heat with it.

As you become more fit, you are able to work harder.

You generate more power on the bike and maintain a faster pace on the run and in the water.

But the ability to work harder also means you have the ability to generate a lot of heat in a very short period of time.

You also have the endurance to sustain exercise longer, meaning you have the capacity to generate heat for a longer period of time.

Your body has to adapt to these demands in order to keep your core temperature stable.

Here are a couple of ways it does that:

You start sweating sooner:

Your body’s sweat response gets quicker as you gain fitness.

This means you’ll see sweat appearing on your skin sooner after you start exercising than you did when you were a novice.

These days, when you start warming up your body knows what’s coming next, so it ramps up the cooling process more quickly to stay ahead of the rise in core temperature.

Your sweat volume increases:

When the house is on fire, you open up the spigots and get as much water on it as you can.

For the fire within, we don’t want to extinguish it but we need to control it, and the more sweat you get onto your skin the more likely you are to be able to keep core temperature from rising out of control.

So your body becomes better at creating sweat.

You lose fewer electrolytes per unit volume:

As your body is adapting to sweat more and sooner, it also changes the composition of sweat so that you retain more electrolytes than you used to.

You’ll still need to replenish electrolytes during exercise, but this adaptation helps to keep the electrolyte requirement manageable.

Fit athletes sweat more because they need to.

They generate more heat and have to produce more sweat in order to maximize their evaporative cooling capacity.

That means fit athletes have to consume more fluid so you have more to contribute to sweat.

But sometimes sweating isn’t enough. 

Or sweat might be enough to keep you moving but you could optimize your performance by helping your body stay cool.

That’s where hydration, apparel choices, ice socks/vests, cold sponges, etc. come into play.

Here are a couple of things to keep in mind:

Hydration is your source for sweat: The better you hydrate – during exercise as well as throughout the day – the more efficient your body will be when it comes to sweat production.

Remember, when there’s not enough fluid to go around, your body starts an internal competition for resources, and all systems experience diminished performance.

You don’t absorb and digest food as well. Your muscles don’t function as well, and you don’t regulate core temperature as well.

Evaporative cooling works just as well whether it’s your sweat or bottled/tap water that’s evaporating off your skin.

Even if you’re well hydrated, it’s a good idea to dump water over your head and body during training sessions and races in hot weather.

You’ll make your body’s job a bit easier by slightly alleviating the demand for sweat.

Ice socks work the same way; the ice absorbs heat from your body to melt the ice. 

And then the water carries away additional heat as it evaporates out of clothing or off your skin.

Electrolyte drinks or carbohydrate/electrolyte drinks should be a part of during-exercise nutrition strategy whenever your workouts are going to be longer than 1 hour.

For workouts shorter than an hour, electrolyte drinks may still be somewhat helpful. 

But generally you’ll start short workouts with enough carbohydrates and electrolytes on board to complete a high-quality one-hour session.

More Info Regarding Sweating Not Just When Your Exercising

And yet, we’re constantly at battle with our sweat: trying to make it stink less. 

Trying to stop it altogether during an important meeting, then trying to lose buckets of it at the gym.

But if you stop and pay attention, all that perspiration can actually teach you a surprising amount about yourself and your health.

Here are a few things it’s trying to tell you.

1. You’re pregnant…or hitting menopause

Anything that toys with your endocrine system (your body’s collection of hormone-producing glands) can leave you feeling sweatier than usual.

Of course, there’s the dreaded hot flash. 

Which as many as 85% of women have in the years right around menopause, but pregnancy may also be to blame.

That’s because hormonal changes seem to mess with the brain’s “thermostat,” mistakenly making you think you’re overheating—and triggering the naturally cooling sweat response—even when you’ve positioned yourself right in front of the AC.

2. You’re stressed

If you keep catching yourself sniffing and wondering, “Is that me?!”, take a sec to reflect on what’s been on your mind lately.

If you’re stressed or anxious, your pits are probably to blame.

The sweat we produce when we’re hot is made by eccrine glands all over the body and contains mostly water and salt.

But when we’re stressed, sweat is produced by apocrine glands, which are found only in certain areas like the armpits.

That type of sweat contains fat and protein that mix with the bacteria on our skin, producing a stench in the process.

Same deal if you’re anxious or scared. (Tired of waking up drenched? Of course you are! 

These super-cute PJs from Rodale’s are made with a fabric that pulls sweat away from your skin 10 times faster than other fabrics, helping keep you cool all night long.)

3. You’re spreading happiness…

…or fear. Oddly enough, the people around you can pick up on what you’re feeling by the smell of your sweat.

In a (rather revolting) experiment, 36 women smelled sweat samples of 12 men who had watched videos meant to either scare them or make then happy.

When a woman smelled sweat from a guy who’d been scared by the video, she was more likely to make a facial expression resembling something like fear.

When she smelled sweat from a happy guy, she was more likely to smile. Guess it can’t hurt to crack a smile at the gym.

4. You’re at risk for heatstroke

Everything’s going swimmingly during your summer walk, when suddenly you realize you’ve stopped sweating and you’re starting to get dizzy.

Anhidrosis, or the inability to sweat normally, can be dangerous, since it prevents your body from naturally cooling off.

If you continue on without rehydrating, you risk heat illnesses like heat exhaustion or heatstroke.

Move to a shady or air-conditioned space and have something cool to drink (without caffeine or alcohol).

If you don’t start to feel better quickly, call for emergency medical attention.

However, longer-lasting anhidrosis may be due to nerve damage, certain medications, or an inherited condition. 

Which can increase risk for heat illnesses and heart problems, too, says David M. Pariser, MD, former president of the American Academy of Dermatology.

It’s pretty rare, though, he says; just because you don’t feel moist and clammy, doesn’t mean you’re truly not sweating.

Turns out, most of us produce about an ounce and a half of sweat every day, not counting those puddles you make when you work out.

If you notice a real drop in your sweat production, be sure to bring it up with your doc.

5. Your blood sugar’s low

Normally, your blood sugar should be between 70 and 100 milligrams per deciliter, if measured when fasting.

But if it drops below that 70 mark, whether because of diabetes or something like strenuous exercise, you may start to feel the effects.

One symptom can be excessive sweating, or cold, clammy skin, particularly at the back of your neck at your hairline.

(Watch out for a quickened heartbeat, shakiness, slight nausea, dizziness, and blurred vision, too.)

Luckily, in cases of a mild dip, you can bring your blood sugar back up to normal by eating or drinking something.

But if your blood sugar continues to drop, you’ll likely start to notice other more serious symptoms and could require medical care.

6. You’re eating the wrong foods

If you’ve been cursed with particularly fishy smelling B.O., you may have a rare genetic disorder called trimethylaminuria, which means your body can’t break down the chemical compound trimethylamine, produced during digestion of foods like eggs, legumes, and fish.

Instead, your body sheds excess trimethylamine via sweat, urine, and breath—often producing a smell not unlike rotting fish, rotting eggs, or garbage, according to the National Institutes of Health.

If you think you may have trimethylanminuria, work with your doctor to come up with the best treatment plan.

Which will likely involve avoiding these foods and possibly popping certain supplements.

7. You might need more to drink than your workout buddy on your next long run

Ever had sweat drip into your eyes, only to find yourself in searing, stinging pain?

Does dried sweat leave a gritty feeling or white streaks on your cheeks, too?

You’re probably a salty sweater, common among people who get lots of water during the day and keep sodium pretty low in their diet.

You’ll probably want to reach for a sports drink or an electrolyte tablet you can dissolve in some H2O sooner than the average exerciser.

8. You could have hyperhidrosis

If a doc can’t find an explanation for your excessive sweating, you may have a condition called primary focal hyperhidrosis. 

When excessive sweating is a medical condition in and of itself.

And no, spinning enthusiast, you do not have hyperhidrosis if you can produce a lake of sweat under your bike.

Primary focal hyperhidrosis is typically marked by sweating so excessive it interferes with your daily activities.

“You’re supposed to sweat when you’re physically hot, or exercising, or stressed,” says Pariser, who’s also secretary and founding member of the International Hyperhidrosis Society.

“People with primary hyperhidrosis sweat at times when they shouldn’t.” Even in a cool room, sitting perfectly still, a person with hyperhidrosis could have sweat dripping from her hands, he says. 

Experts aren’t entirely sure why it happens. 

But they do know that hyperhidrosis runs in families and is the result of too much stimulation from the nerves that trigger the sweat glands.

“The switch is stuck in the ‘on’ position,”

Pariser says. Depending on the location of the sweating, hyperhidrosis treatment varies, but can include prescription-strength antiperspirant (even on the hands and feet), Botox injections, and surgery.

9. You could have lymphoma

Hyperhidrosis can also be a side effect of a number of health conditions—including gout, hyperthyroidism, and Parkinson’s disease—and even some medications.

Particularly troubling is that it can be a symptom of lymphoma, or cancer of the lymph cells, which play a role in the immune system.

It’s not completely understood yet why lymphoma can cause drenching sweat; it could be something about lymphoma itself or how the body responds to it, Pariser says.

Perhaps it’s a reaction to another symptom—fever—as the body tries to cool itself down. (Both fever and sweating are known as “B” symptoms and linked with more aggressive lymphoma).

Or, it could be caused by hormones and proteins produced by cancer cells themselves, according to the UK Lymphoma Association.