Why Do I Sweat More Than Everyone Else

If your shirt is soaked by the end of the warm-up while the person next to you finishes the same session almost dry, that is usually not a sign of poor conditioning. Sweating is a cooling system, and how hard it runs depends on body mass, genetics, training status and gym conditions. Here is what is actually behind it, and which parts are worth changing.

Sweat is cooling, not detox

When you squat or run, your muscles turn roughly 75 to 80 percent of the energy into heat and only the rest into movement. That heat pushes your core temperature up, and if the body did nothing, 15 to 20 minutes of hard work would raise it by more than 2 degrees. So your sweat glands open, and you have somewhere between two and four million of them.

One detail matters more than anything else here: sweat only cools you when it evaporates. The drops running down your back and hitting the floor did no work at all. Evaporating one litre of sweat removes about 580 kilocalories of heat, which is why a fan and thin clothing help more than any drinking trick.

Why you sweat more than the next person

Body mass

A bigger body produces more heat for the same job. A 100 kg person on a treadmill at a given speed generates roughly 30 to 40 percent more heat than a 72 kg person, and has more mass to cool. If you have gained 10 kg over the past year, the same workout will visibly soak you more.

Better conditioning means more sweat

This surprises people: trained people sweat earlier and more heavily. After 8 to 12 weeks of consistent training, the body starts sweating at a lower core temperature and loses less salt per litre. Sweat rate can climb from around 0.8 litres per hour to 1.5 to 2 litres per hour. That is an adaptation, not a fault.

Genetics and active gland count

How many glands actually switch on varies between people and you cannot change it. Someone with your weight, your program and your fitness level can sweat half as much.

The room

The difference between a gym at 21 and one at 27 degrees is huge. Humidity matters even more: above 60 percent, sweat evaporates poorly, so the body keeps producing more of it and you end up wetter without being cooler. A 6 pm summer session produces far more sweat than the same session at 8 am.

Coffee, spice and alcohol

200 to 400 mg of caffeine (two to three coffees) raises body temperature and heart rate. Spicy food, and alcohol the night before, both push sweating up as well.

Measure your own sweat rate

Instead of guessing, do this once in a warm period and once in a cold one:

1. Weigh yourself before training, in underwear and after using the bathroom.
2. Train for exactly 60 minutes and write down how many millilitres you drank.
3. Towel off, remove wet clothing, and weigh yourself again.
4. The math: (kg before minus kg after) times 1000, plus the fluid you drank in millilitres.

Example: 82.0 kg before, 81.1 kg after, 500 ml consumed. That is 900 plus 500, so 1400 ml of sweat per hour. Anything above 1.8 litres per hour is genuinely high and worth planning your drinking around.

What to do in practice

• Before: 400 to 600 ml of water 2 hours out, plus another 200 ml half an hour before you start.
• During: 150 to 250 ml every 15 to 20 minutes. Do not wait for thirst if the session runs past 60 minutes.
• Salt: if you lose more than 1.2 litres per hour, or white salt marks dry onto your dark shirt, add 300 to 600 mg of sodium per litre of water. One gram of table salt gives about 400 mg of sodium, so a pinch of roughly one gram in 500 ml does the job.
• After: drink 1.25 to 1.5 litres for every kilogram lost, spread over the next 2 to 4 hours, alongside a meal that contains salt.
• Environment: stand in front of a fan, stretch rest periods to 90 to 120 seconds instead of 45, and wear thin clothing that breathes. Two towels is a solution, not an embarrassment.

Performance starts dropping at a loss of about 2 percent of body mass. For an 80 kg lifter that is 1.6 kg, which heavy sweaters reach in about ninety minutes of summer training.

When to see a doctor

• You sweat at night enough to change sheets or pyjamas, and it has lasted more than 2 weeks.
• Sweating comes with weight loss you did not plan, say 4 to 5 kg over a few months, or with a fever.
• You sweat heavily at rest along with hand tremor, a fast pulse and poor heat tolerance. That warrants a thyroid check.
• Sweating arrives together with chest pain or pressure, nausea or shortness of breath. That is an emergency, call for help immediately.
• Your palms, feet or armpits are soaked with no exertion at all, for more than 6 months, and it interferes with work. Hyperhidrosis is treatable.
• The sweating started after you began a new medication.
• During training in heat you stop sweating, your skin turns hot and dry, and you feel dizzy or confused. That is heat stroke and needs emergency care.

The short version

• Sweating cools you and depends on mass, genetics, fitness and room conditions, not on how bad you are at training.
• The fitter you get, the earlier and more heavily you sweat. That is a good sign.
• Measure your sweat rate by weighing yourself before and after 60 minutes of training, and plan fluid around the number.
• Replace 1.25 to 1.5 litres per kilogram lost, with 300 to 600 mg of sodium per litre if you are a heavy sweater.
• See a doctor for night sweats, unplanned weight loss, resting sweat with a fast pulse, or sweating with chest pain.