5 weird things that happen to your body when you try a new form of exercise

It’s the (unofficial) start of a new season, so naturally you’ve decided to embark on a fresh fitness routine. Congratulations! But wait a minute. How come your “new and improved” bod is feeling kind of weird after you tried that spinning class for the first time? Is this normal? Actually, yes. It turns out that your body can bust out some funky moves when you try a new kind of exercise for the first time—and we’re not referring to your Zumba class.

As you begin to adapt to your new fitness routine, weird things will happen to your body, like nausea and even clumsiness. It’s important to remember that these things are totally normal and should dissipate with time (if they don’t, please seek advice from your doctor).

We talked with a couple of experts to get the low-down on five weird things that happen to your body when you try a new exercise. Here’s what you need to know:

1. Tummy troubles

“Runner’s trots” might sound like the name of a functional warm-up, but it’s actually a slang term for diarrhea that can occur after a long bout of intense aerobic weight-bearing exercise, like running or step aerobics.

“The specific cause is unknown, but it’s theorized that a combination of the jostling movements, massage-like contractions of the abdominal wall, and change in oxygen availability to the digestive tract all play a role in post-workout diarrhea,” said nutrition coach Dr. Gabrielle Fundaro.

To ward off those post-workout poops, Dr. Fundaro recommends avoiding high-fat or high-fiber meals within a couple hours of exercise, and hydrating with a proper sports beverage if you’ll be exercising for longer than an hour.

2. Nausea

If “runner’s trots” isn’t enough trouble for your tummy, you might also encounter nausea after trying a new weightlifting workout.

“When I have a new client who has not been participating in a strength-training regimen, I always warn them it’s normal to feel a bit nauseated after the first and possibly second workout,” said Laura Arndt, a certified personal trainer, Pilates instructor, and CEO of Matriarc, a digital health and wellness company for new moms. “Many clients will actually throw up the first time they lift weights, even if it’s not super strenuous. Your body builds up carbon dioxide and lactic acid, creating a higher level of acidity in your body, and this can make you feel sick.”

To help prevent any nausea, Arndt recommended eating only small meals within an hour or two of exercising. “Also, easing into a new exercise is best,” she said. “Don’t go full force on your very first try at something. Give your body some time to adjust.”

As your body adjusts to the new workout, the nausea should disappear.

3. Funky weight fluctuations

Have you been tackling a new high-intensity workout and you’re still not seeing results? In fact, do you think you’ve even gained weight? Dr. Fundaro said that’s quite normal.

While the scale is just one metric of success—and not a particularly accurate or reliable one—it’s a convenient way to monitor your weight by noting trends over time.

“Some people are frustrated to find that their weight unexpectedly increases after a particularly strenuous gym session,” she said. “This is neither body fat nor muscle mass (gaining either one takes time) but is in fact water retention due to inflammation. It’s a natural part of the reparative process post-workout.”

While there’s no treatment for this nor is it preventable (sorry!), Dr. Fundaro said it’s prudent to stay hydrated.

“The general rule of thumb is to aim for 1 ml of water per calorie that you’re eating, and an additional 2-3 cups of water after your workout,” she said. “If you wake up feeling sore and your scale weight has unexpectedly increased, rest assured that there is an association here and daily fluctuations are normal.”

If you’re trying to lose weight and want to track results, rely on progress pictures, circumference measurements, or noticing how your clothing fits, because the scale isn’t always the most reliable measurement of progress.

4. Clumsiness

Feeling a little off-balance during your new barre class? Yep, that’s all part of the process of your body getting stronger.

“You will probably feel uncoordinated and clumsy when you start a new exercise,” said Arndt. “Part of being in shape is muscle memory. Your brain learns a motion, and then the second time you complete the activity, your brain helps you recruit more muscle fibers faster to make the exercise more effective. However the very first time [you try the exercise], your brain and body are not quite in sync and you may feel a bit wobbly when trying to get through the workout—especially if it involves balance!”

In order for the body to learn a task and improve muscle memory, also known as motor memory, Arndt said it needs to be done multiple times so it can become automatic. So hang in there!

5. Super soreness

It’s inevitable. You will feel super sore days after trying a new exercise. Don’t worry, you’re going to be A-OK.

“Most people have heard of ‘DOMS,’ or delayed-onset muscle soreness. This is the achy soreness that picks up about one to three days after a strenuous workout and seems particularly painful when you’re stretching the worked muscle,” said Dr. Fundaro. “Contrary to popular belief, this is not caused by a buildup of lactic acid, but in fact by microtears in the skeletal muscle. It’s a normal part of the reparative process that accompanies water retention.”

While feeling sore is normal, Dr. Fundaro noted that adhering to the “no pain, no gain” principle isn’t exactly what you’re aiming for.

“You want to follow a progressive plan that builds up gradually,” she said. “You won’t reap additional benefits by pursuing a feeling of soreness.”

So now you can hit the gym with the reassurance that all those weird things happening to your body are just helping you to become stronger than ever.