There Is a Link, but No Cause and Effect
Everyone has a different threshold for sweat just as people have different thresholds for tears. It would be irrational to assume someone who is always crying to be emotionally healthy, just as it would be to assume someone who is always sweating is physically fit. There is some correlation, but there is no direct cause and effect. Some people react to stimuli by sweating, some people sweat regardless. There are persons who may get their heart rates up and have very little visible sweat. There are also people who barely push themselves, yet are sweating profusely.
Fool's Gold: Obvious Choices Can Lead to Uneducated Decisions
Sweat is one of many reactions the body can go through, the reaction that is most important is that of adaptation. We rely on sweat because it is obvious. You can see it, smell it, feel it, and sometimes you can hear it dripping onto the floor — fool's gold. What we cannot see with the naked eye, initially, is if any of that made your body better. Sweat, like a "red herring," is a clue that can be misleading.
Sweat Obsession Can Create an Unhealthy Mindset
Sweat may foster instant gratification. It is possible to sweat enough where you will be lighter than when you started. That's not "real" weight loss, that's just the amount of sweat you've lost. You will have to replenish that water or face serious health consequences. You can have the same weight loss results from not drinking water, but the dangers and frivolity of that method are more apparent.
Being upset that an acorn didn't turn into a mighty oak tree overnight may cause you to uproot that acorn and try something else. In the future, when there is no oak tree, will you associate it with your actions in the past? If you only pay attention to those instant reactions, like sweat, you may not. You may always be in a state of confusion and limbo, losing weight and getting fit for brief periods accidentally, not ever knowing what triggered those adaptations. An oak tree is merely an acorn that stood its ground.
Sweat is not fat crying, just as incessant crying will not melt away depression. Looking for more things to cry about can make depression worse, just as looking for ways to sweat more can ruin muscle. Hard work is hard work, whether you sweat, bleed, or cry.
Not Real Weight Loss but Real Physical Damage
Working out only to induce sweat (using heat, clothing, excessive intensity, duration, or cardio) can create a vicious cycle where hunger increases more than normal. You may convince yourself that you can eat more since you've compensated by sweating, and are actually down on the scale from water weight — one of the many ways we inadvertently gain weight while exercising. It is not because muscle weighs more than fat, it is because you've gained more weight than you've lost. Our bodies and minds will play tricks because they are that depleted.
To temporarily make us feel better, our bodies will produce tears and sweat as a reaction to recent strain. It isn't something that indicates long-term development and can become a crutch. Sweat or no, the focus shouldn't be on the short term byproducts, the focus should be on creating the right training adaptations. If you happen to sweat, great. If you don't, so what? I suspect with better technology and trackers, we will have better ways to track the intensity of a workout. If you are broken down to tears or vomiting from exercising, you have pushed too far. Exercise isn't a form of punishment, it's supposed to make us better than when we started.
Summary
Correlation is when two things are related, like tears and healing, sweat and fitness. Sometimes healing causes tears but crying does not necessarily mean healing. The same is true of sweat, sometimes physical adaptation causes sweat, but sweat does not cause adaptation. Track your workouts, track what you eat, track how you sleep, and track your measurements. Have enough data to separate the signal from the noise. The focus of a workout should be on improvement, not great dramatic effect.
