How Much Do You Really Sweat? Here’s Why You Need to Know
I’m convinced that I sweat more than any other human being on the planet.
At bit dramatic? Possibly. But the fact that I finish a 30-minute run looking like I just got out of the pool gives some credibility to my claim.
And while I might not actually be the sweatiest person alive, having a sweat rate of 4+ lb. per hour is rough as an endurance athlete, especially one who lives in Florida…
The thing is, sweat rate and composition vary widely from person to person based on factors like genetics, fitness level, weather, and workout intensity.
For example, I sweat a lot, but my sweat isn’t that salty. My husband, on the other hand, doesn’t sweat as much, but he’s a very salty sweater as evidenced by the white, crusty marks on his kit at the end of a hard session.
Also, your sweat rate may differ based on the type of workout you’re doing. Most of us sweat more heavily while running than when riding a bike.
Fun fact: The sweat rate of humans is 2X higher than camels 🐪🐪, and we’re 5X sweatier than horses! 🐎🐎🐎🐎🐎
Why is any of this important?
Sweat is the body’s way of offloading heat during exercise. As sweat evaporates from the skin, it carries excess heat with it, which helps lower core body temperature. This is important if you want to continue exercising for an extended period of time (especially 70.3 or Ironman).
The downside of sweating is it leads to rapid fluid and electrolyte loss, which carries over into a reduction in blood volume and increased cardiovascular strain. Therefore, it’s essential that we replace what we’re losing in our sweat, or suffer a dip in performance or serious health consequences.
One study found that athletes who replaced an adequate proportion of what they’d lost in their sweat finished a 70.3 Ironman 26 minutes faster than the group that didn’t! And while those results aren’t guaranteed, it just goes to show the massive performance gains you can see from properly fueling your body.
Four Areas Impacted by Dehydration:
50-60% of our body weight comes from water, and when you don’t have enough- either from losing fluid during exercise, or not replacing an adequate amount- it leads to dehydration.
Four areas impacted by dehydration include:
Performance- Reduced endurance and aerobic capacity, increased RPE (rate of perceived exertion), and greater fatigue
Heat regulation- Increased risk of heat exhaustion and heat stroke. Especially important during hot and humid conditions
Muscle cramps and fatigue
GI distress- Reduced blood flow to the gut can lead to nausea, vomiting, and stomach cramps
But knowing exactly how much to drink, and what to drink, can be a challenge, especially for athletes new to endurance sports.
“I drink a bottle per hour on the bike. That’s good enough, right?”
Well, that depends. How big is that bottle? 16 oz., 18 oz., 20 oz., 25 oz., or 32 oz.?
What’s in the bottle? Fluid, electrolytes, carbohydrates?
One thing that can help dial in your hydration needs is sweat testing. And that’s the topic of our Monthly Expert Chat tonight! (7/22/2025 at 6 pm EST)
Lexi Kelson of Precision Fuel & Hydration will join us to talk about what sweat testing is, how it works, and how you can use sweat testing to dial in your training and race day plan.
The full webinar- Get the 411 on Sweat Testing- is an exclusive for paid members of the Triple Threat Life Club.