How Does the Body Maintain Homeostasis During Exercise?

During exercise, your body goes through lots of processes: You're sweating, breathing heavily and moving your muscles and joints. These processes are all signs that your body is hard at work maintaining homeostasis, also known as your body's equilibrium.

Sustaining homeostasis is important for regulating your body's internal balance so that all of your organs and cells function properly.

But how does your body maintain balance when all of your systems are in flux during exercise? Here's everything you need to know about homeostasis and how exercise affects it.

Homeostasis refers to the steady state of all your body's systems, including body temperature, fluid balance, resting heart rate and blood sugar levels, that keep your body balanced and functioning optimally, says Stacy T. Sims, PhD, an exercise physiologist and nutrition scientist.

"This means our body's acid and base levels are balanced, and our cells, organs and systems can function well," says Heather Milton, MS, CSCS, a clinical exercise physiologist at the NYU Langone Health Sports Performance Center.

Exercise affects your homeostasis in a variety of ways, such as raising your body temperature, increasing the need for more oxygen and changes in blood sugar and fluid balance.

"When we exercise, we cause a disturbance in this equilibrium by pushing systems out of their normal resting preset limits," Sims says. "For example, one of the first things that people notice is an elevation in heart rate. This occurs because there is an increased demand for blood to the working muscles, and the muscles have a higher metabolic demand (needing oxygen for fuel conversion and to remove metabolites)."

There are built-in mechanisms that your body uses to buffer the changes in your internal systems so you can maintain homeostasis. Adaptive homeostasis is what happens during exercise because your heart rate, blood pressure, cardiac output and respiratory rate adjust to the intensity of your workout, Sims says.

"Exercise stimulates the sympathetic nervous system and will induce an integrated response from the body. This response works to maintain an appropriate level of homeostasis for the increased demand in physical, metabolic, respiratory and cardiovascular efforts," she explains.

Glucose from the foods you eat is used up by your muscles for energy, and as a result of that, your pancreas reacts by changing insulin levels to maintain blood sugar, Milton says. The more intense your workout is, the more oxygen your body needs to convert food into fuel.

"Energy stored within muscle is also used at higher-intensity [exercise] to a larger extent. These stores are limited, so that's why extremely high-intensity exercise, like sprinting, can't be maintained over longer periods of time. Our liver helps produce energy to restore these levels," Milton says.

During exercise, there is also an increased demand for blood to your working muscles, so your body responds by increasing your heart rate.

Your body increases heart rate during exercise by stimulating your sympathetic nervous system (the part of your autonomic nervous system that controls your "flight-or-fight" response) at a greater rate to overcome parasympathetic (the part of your autonomic nervous system that signals relaxation) responses, Sims says.

Your adrenal glands also excrete norepinephrine and epinephrine (neurotransmitters) to balance where blood in your body is distributed, re-directing blood flow away from your digestive system and to your cardiovascular, respiratory and muscular systems, Milton explains.

When you're working out, your body redistributes blood flow to your skin and working muscles. At the same time, you sweat, and when sweat on your skin is evaporated, it cools the skin, Milton says.

According to the Mayo Clinic, sweating is one way our body cools itself. Your nervous system triggers sweat glands as your body temperature rises while working out.

The more you consistently exercise, the more your body adapts to achieving exercise homeostasis, Milton says.

"Chronic exposure to this adaptive homeostasis is what we think of as improved fitness and health outcomes because the body adapts and becomes more efficient at performing an exercise," Sims says.

These adaptations include increased endurance, muscle strength and bone density.

Drinking water during exercise helps with maintaining homeostasis because it helps replenish fluids that are lost via sweat. Your body needs fluids to carry nutrients to your cells and organs to function properly.

If you're working out for more than an hour, particularly in a hot and humid environment, you may benefit from having a sports drink to help replenish electrolytes (salt and potassium) that are lost in sweat, Milton says.

It's a common mistake to hold your breath during hard efforts, like lifting heavy weights or doing a plank, but doing so decreases your body's ability to maintain homeostasis.

"We have chemo and baroreceptors (sensors that regulate respiration and circulation) in our body that initiate reactions to increase breathing depth and rate during exercise," Milton says.

Your body needs fuel to perform well during exercise. Make sure to enjoy a pre-workout snack and avoid high doses of caffeine, Sims says.

Avoid jumping right into your workout and do a quick warm-up to wake up your muscles and joints. After your workout, spend some time doing a cooldown to redistribute blood flow to your organs and improve muscle flexibility and joint range of motion.