No one likes when her face is too damp to apply makeup on summer mornings or when it seems like every white shirt you own is permanently discolored, but sweat is actually the body’s (pretty brilliant) built-in cooling system. Your body temperature rises, your nervous system gives your sweat glands the green light, and moisture pops onto your skin, where it promptly (well, eventually) evaporates, cooling you down in the process. (Not feeling as well as you used to?
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.
You need more sodium
Salty sweat is your body’s request for more sodium. If your sweat stings your eyes, burns in an open cut, leaves a gritty feeling on your skin, or produces white streaks on your face or clothes, it could be your cue to amp up your sodium intake. Add salt to foods such as eggs, vegetables, or meats, and drink a sports drink rather than plain water when you exercise, advises Runner’s World
You might need to kick the coffee habit
Too much java could be to blame for the sweat circles that appear on your morning commute. “Coffee increases perspiration in two ways,” Liz Lyster, MD, of Holtorf Medical Group in Foster City, California, told Huffington Post. “First, caffeine stimulates the central nervous system, activating sweat glands so the more caffeine you have, the more you sweat. Secondly, the heat from the drink itself can make your body feel hot enough to sweat.” If you can’t kick your coffee habit completely, opt for iced or decaf.
You’re applying antiperspirant at the wrong time
“Antiperspirants are most effective when applied to very dry skin,” David Pariser, MD, founding member and secretary of the International Hyperhidrosis Society, told Woman’s Day. “If you apply them in the morning right before you head out, or right after you get out of the shower, you’ll likely already be sweating or have wet underarms. If the skin’s surface is wet, the chemical reaction that forms from the aluminum [in the antiperspirant] will happen on the surface of the skin instead of in the pores, preventing the sweat glands from getting blocked.” Even if you’re a morning shower taker, use antiperspirant at night before bed. When applied to totally dry skin, the product can last for a few days. Post-shower, apply a deodorant for fragrance and you’ll be good to go.
You’re scared
A U.S. military experiment suggests that people can literally smell fear. For the study, researchers collected sweat samples from 20 novice skydivers before and during their first tandem jump, and then again as they ran on a treadmill for a similar duration of time. Volunteers in brain scanners were asked to take a whiff of each sample. The brain regions associated with fear were more active when the volunteers sniffed the skydiving sample than the treadmill sample. The results make sense from an evolutionary standpoint—one person’s fear pheromone would alert those around him that danger is in the air.
You’re overcoming an illness
Think your cube-mate smells a bit off this week? They might just be sick. One Psychological Science study found that healthy people are able to detect the amped-up immune system of someone fighting an infection. The results suggest that smell is an important warning signal against contagious illnesses. These are clear signs you’re getting sick.
Your fitness goals are on track
If you break a sweat earlier in a workout than usual, it doesn’t indicate that your endurance has fallen behind. In fact, it should signal the exact opposite. In one 2010 study, researchers found that fitter people not only tend to sweat at a greater volume, but they also start sweating sooner. “A high fitness level allows you to exercise at a higher workload, which generates more heat, which in turn leads to more sweat,” Craig Crandall, PhD, a professor of internal medicine at the University of Texas Southwestern Medical Center, told Time.com.
You’re depressed
In healthy people, environmental changes—things that make us scared, stressed, happy, or nervous—have an impact on both the volume and odor of sweat. But when a person is depressed, that response to stimuli declines. One German-Swedish study found that this reduced response was present in up to 97 percent of depressed patients who later committed suicide. “It was probably the case that certain nerve cells in the hippocampus are damaged by depression and negative stress,” Lars-Hakan Thorell, one of the researchers behind the study, said in a press release. “A depressed person has a biological inability to care about the surroundings, while a healthy person continues to react.”
You’re giving off good vibes
If you smile while you sweat, those around you smile too. At least, that’s what one Dutch study suggests. For the experiment, 36 women smelled sweat samples from 12 men who had watched videos meant to either scare them or make them happy. When a woman took a whiff of a scared guy’s samples, she was more likely to make a facial expression resembling fear. When she smelled the happy dude’s sweat, she was more likely to smile.
You’re pregnant
Unusually intense sweating during pregnancy is a common complaint from expectant mamas. It’s a result of an increase in hormones, blood flow, and metabolism, Mary L. Rosser, MD, PhD, told TheBump.com. Night sweats tend to occur in the first trimester of pregnancy. Hot flashes also occur during menopause as a result of similar hormonal imbalances.
