You might sweat less, if at all, during a strength training workout than you might during a run or spin class – and that’s okay.skynesher/Getty Images
As someone who used to be cardio-obsessed, one aspect of strength training has always seemed odd to me: I often feel like I’m working hard, yet I barely ever break a sweat. While even the most casual 5K often left me soaked in sweat, a 45-minute strength session, which felt much more strenuous, produced barely a bead.
I often wondered if my strength-training workouts were effective if I wasn’t perspiring.
Greg Heatherington, founder of Toronto’s Fuel Training Club, understood my concern because he’s seen many people like me in his classes. First-timers often do jumping jacks or jog in place during rest breaks or while a trainer explains the workout.
Why do some people gain more muscle than others?
“I think a lot of people are looking for the quickest path to success,” he says. “And perceived success is often associated with more sweat.”
But whether you perspire and how much aren’t the telltale signs of effort that you might think they are.
“Sweating is not good or bad,” says Paul Dorian, a cardiologist who leads the sports cardiology clinic at Toronto’s St. Michael’s Hospital. It’s simply our body’s way of cooling down. Observing your sweat rate can help you determine water loss and hydration needs, he adds, but it’s not a measure of effort.
If sweat doesn’t automatically equal a caloric burn, and if it’s not a sign that I’m working really, really hard, then what exactly does it mean?
Why do we sweat during a workout?
When you exercise, the friction of your muscles moving against each other produces heat, explains Dorian. The more friction and the more repetitive the movements, the more heat you’ll generate, and the more you’re likely to sweat.
“That heat that’s generated has to be dissipated,” says Dorian. The evaporation of the beads of sweat on your skin is your body’s way of cooling down.
But how much you do or don’t sweat, and how that differs from the person next to you, isn’t solely based on your levels of intensity.
Men, for example, often sweat more than women, says Dorian. The temperature outside or inside a studio has an impact, as does the clothing you’re wearing. Trained athletes tend to sweat more because their bodies have adapted to respond quickly as their core temperature rises.
It’s okay to not sweat during a strength training workout
In a strength workout, in which you’re lifting a weight for several repetitions, putting it back down, and resting several minutes, you might sweat less, if at all. That’s because your body temperature isn’t rising as high as it might during a workout in which you’re in constant motion, like a run or a spin class.
But “whether you’re sweating or not doesn’t necessarily equate to you burning more calories,” says Heatherington.
Guide to lifting weights: How to reach your strength, size and stamina goals
Instead, you can measure your work level and intensity using what’s called the Reps in Reserve scale: at the end of a set, you should feel like you only have two or three more repetitions left in the tank before your form breaks down.
“I would strongly disrfercourage your readers from using sweat as a measure of anything,” says Dorian. “It’s just a measure of water loss but it’s not a measure of how hard you worked.”
I still want to sweat! Do I really need to rest during a strength workout?
If you really love the feeling of a good sweat, mix some cardiovascular work into your training schedule. Just make sure that during hotter weather, you’re paying attention to signs of heat exhaustion, which include weakness and dizziness. While sweating can be a sign of heat exhaustion, if your body stops sweating completely and your skin is dry to the touch, that can be a sign of heat stroke, which can be life-threatening. If that happens, stop and seek medical attention.
If you know you’ll be exercising in the heat, make sure to drink fluids before and during your workout (if possible) and add electrolytes to your beverage to replace the sodium lost through sweat.
In strength training, regardless of whether you feel tired or hot, and even if you’re working out in an air-conditioned gym, resting between sets is necessary. An easy rule is to rest for about three minutes between sets of a single exercise.
“If you don’t rest enough, you’ll notice that you’re not able to do the same number of reps or lift the same amount of weight,” says Heatherington. And that’s a crucial part of strength training. To see results, you have to keep challenging your muscles.
When your heart rate starts slowing down, that’s your nervous system recovering from the work you just did, and that’s what will allow you to put in the work for your next set.
If you’re used to doing a lot of cardio, you might start doing your strength training workout and feel like you’re not doing all that much. You have to be willing to keep going for a bit to really see results, says Heatherington. “Strength training is really about trusting the process.”
Alyssa Ages is a journalist and the author of Secrets of Giants: A Journey to Uncover the True Meaning of Strength. She is also a strongman competitor and endurance athlete, as well as a former personal trainer and group fitness instructor.