• Exercising can make you feel great, but some of your workout habits could be hurting you. 
• You shouldn't be in lots of pain because of a workout, so you should reassess your routine.
• Getting sick often, not sleeping well, or losing your appetite are signs you may be overtraining.

What you think are healthy exercise habits might actually be hurting you or putting you at risk for injury. 

If you're on a fitness journey this New Year, Business Insider spoke with training experts about the common signs your workout could be hurting you.

If you're in any amount of pain, stop what you're doing.

Jasmine Marcus, a New York-based physical therapist, told BI why pain during your workouts is a recipe for disaster.

"Pain is your body's way of protecting you and it most likely means you are injuring yourself," she said.

If the pain is localized to one body part, and you're able to finish a workout, Marcus said, you can continue working out as long as you're sure to seek medical treatment for whatever it is that is bothering you.

"For example, if your shoulder is bothering you, you should avoid irritating it further with shoulder presses, but there's no reason you can't keep working out your lower body," she added. "Just make sure to eventually seek out treatment for your shoulder."

Always listen to your body because toughing it out through an injury could end up sidelining you longer. If your pain is sharp, stabbing, or severe, or if you experience swelling, bruising, or any sort of open wound, you should seek medical assistance.

Working out shouldn't make you dizzy or weak for extended periods of time.

If you're experiencing dizziness or feeling weak long after your workout, that's not a good sign.

Mitchell Starkman, a sports and orthopedic physical therapist based in Canada, told BI that some dizziness is normal, but it shouldn't persist.

"If you're consistently getting dizzy while working out, it's always a good idea to follow up with your doctor first," he said, "That being said, many people become temporarily dizzy while training during position changes."

Starkman added that, similar to feeling light-headed when you stand up too fast, this dizziness comes from your body readjusting to the pressure change caused by sudden movements (like squats or deadlifts), which can lead to a "momentary lapse of blood flow to the brain."

Another reason for dizziness could be your eating habits. Every person's dietary needs vary, but if you're frequently working out on an empty stomach, it might make you feel woozy during a workout.

Your workout routine could be to blame if you keep getting sick.

Consistent exercise can boost your immune system, however, overtraining can backfire and cause you to get sick.

"Exercise is an amazing thing, and it, when done consistently, actually boosts our immune system over time," Starkman told BI. "That being said, when it's too intense, after our workouts, the body's immunity actually slightly drops for a few hours, making us more susceptible to sickness."

If you're constantly getting sick, you might want to reassess your fitness regime and make sure you're planning enough rest days and properly fueling your body before and after your workouts.  

If you're having trouble sleeping, it might be from overtraining.

Exercise is thought to benefit the quality of your sleep, but if you're lying awake at night tossing and turning, it means you might be overtraining.

"Insomnia is a sign that your sympathetic nervous system is not functioning healthily and is directly linked to exercising too much," Chelsea Axe, a board-certified chiropractic physician and certified strength and conditioning specialist at DrAxe.com, told BI.

She continued, "An overactive sympathetic nervous system and trouble sleeping are more closely linked to anaerobic activities, like sprinting, and especially heavy resistance training, like weightlifting."

Since the sympathetic nervous system is closely connected to the brain's fight-or-flight response, these kinds of exercises can easily cause insomnia or restlessness. Working out earlier in the day or scaling back on workout frequency and intensity can help alleviate sleep issues tied to your workout.

"Exercisers with signs of an overactive sympathetic nervous system could benefit from regular meditation, gentle yoga, and massage," Axe said. 

In addition to messing up your sleep schedule, your routine may be causing extreme fatigue.

If you find yourself feeling tired all the time or leaving the gym feeling exhausted instead of energized, you might need to scale it back.

"Sore muscles are common with a new routine, but excessive fatigue is not. If you are getting adequate sleep and are still super tired, there [might be] a couple of reasons," Megan Ostler, a registered dietitian and the director of nutrition at iFit, told BI.

One common reason for it, especially in women, is iron deficiency anemia.

"When we are deficient, we can't transport as much oxygen, and without enough oxygen, our muscles and organs can't perform the way they should, including converting nutrients to energy," she said. "Low energy production means low energy for us."

Another common reason for fatigue is not consuming enough calories pre- and post-workout.

"Our bodies work hard to make sure we don't die from starvation, so when our food intake decreases or exercise increases, our bodies must adapt," Ostler told BI. 

Loss of appetite is also a sign of overtraining.

Although it's true that you might find yourself hungrier than usual as your body adapts to a new fitness routine, suddenly finding that you're never hungry should set off some alarm bells.

"Many athletes assume that they can just follow their hunger cues to know how much to eat. However, that isn't always the case," Ostler told BI. "If you are working out at a high level your appetite might actually be suppressed."

Depression or irritability can be unwanted side effects of working out too much.

When we sweat, our body releases endorphins, the feel-good hormones that make us feel relaxed and alleviate stress. However, Axe said, exercise can actually also lead to spiked levels of anxiety or depression.

"Too much aerobic activity can lead to parasympathetic overtraining," she said. "Symptoms of this include fatigue, depression, and impaired sports performance."

She continued, "Overtrained athletes can also suffer from adrenal dysfunction, in addition to mood disorders exacerbated by excessive cortisol levels in the body."

If your heart is racing long after your workout, you might be overdoing it.

A telltale sign that you're overdoing your workout routine is if your heart rate is fluctuating at rest.

"If you're new to exercise, variation in resting heart rate is expected as your body gets into better shape," Axe said. "But for seasoned exercisers, heart rate variability may be an easy way to pick up on early signs of overtraining."

Persistent muscle aches may be a sign that you're injuring yourself.

Muscle soreness is common in the days after a particularly strenuous workout, but it shouldn't completely sideline you — and it should go away relatively quickly.

If your muscles are constantly sore and achy, you might be overtraining.

"When you work out, you cause small micro-tears to your muscles," Emily Paskins, a personal trainer at iFit, told BI. "This breakdown is then built over, which causes muscle growth. However, if you are constantly 'tearing' the muscles down without allowing adequate time for them to rebuild, you will begin to cause a state of constant wear and soreness."

This story was originally published in May 2018 and most recently updated on January 8, 2025.

Read More:

• 17 exercise habits that are actually hurting you
• 21 sneaky signs you're stressed — even if you think you aren't
• 9 warning signs you're running too much

• Jane Fonda, 87, says her workout routine hasn't changed much over the years.
• "I essentially do everything I used to do, just slower," Fonda told People, adding that she loves walking.
• Research has shown that walking just 4,000 steps a day can lower a person's risk of dying early.

Jane Fonda may be 87, but she's still as fit as a fiddle.

In fact, her workout routine hasn't changed much over the years, the actor told People in an interview published over the weekend.

"I essentially do everything I used to do, just slower," Fonda said. "I used to be a runner, but now I love walking. I love being outdoors in the woods, especially up and down hills."

Regardless of her schedule, Fonda ensures that she gets a bit of exercise every day.

"I work out every day, so it is important to mix up the way I move. I alternate days doing upper body and lower body work for strength. I also find some way to get cardio in. Walking outside is one of my favorite ways to do so," she said.

The actor has long been passionate about fitness. In the '80s, she released a series of home workout videos, beginning with "Jane Fonda's Workout" in 1982.

Looking back at her home workout tapes, Fonda said she had "no idea" they would become so popular.

"When I was starting out, there weren't many rigorous forms of exercise available to women," Fonda said. "I learned the basic workout from a charismatic teacher named Leni Kasden in the '70s."

After the videos were released, she would receive "amazing letters from around the world" from fans about how the workouts impacted their lives, she added.

"One was from a young woman in the Peace Corps in Guatemala who did the exercises in her mud hut," Fonda said. "Another woman said she looked in the mirror as she was brushing her teeth and noticed new muscles in her arms. She wrote that it made her feel empowered, and that day she went to work and stood up to her handsy boss for the first time."

Walking can help you live longer

For those who lead sedentary lifestyles, the best thing they can do for their health is to start somewhere, Dr. Suzanne Steinbaum, a preventative cardiologist, told Business Insider previously.

"Doing something is better than doing nothing," she said. "If walking is the beginning stages of embracing a heart healthy life, then it is the initial stages that will create habits that will be sustainable and last for a lifetime."

A study published in the European Journal of Preventive Cardiology in 2023 found that walking just 4,000 steps a day can lower a person's risk of dying early.

Research shows that walking can help reduce stress and anxiety while improving heart health. Some studies also suggest that brisk walking — at about 2.7 to 3 miles an hour — can make a bigger difference in terms of health benefits.

A representative for Fonda did not immediately respond to a request for comment sent by BI outside regular hours.

• Business Insider asked experts what red flags to look out for when hiring a personal trainer.
• A good trainer shouldn't force you to push through pain or attempt to diagnose it.
• Avoid choosing a professional that lacks empathy or has an ego-driven approach to training.

Hiring a personal trainer can be a transformative step toward achieving your fitness goals, but it's crucial to choose the right professional for your needs.

Although many trainers are dedicated and knowledgeable, some may not be the best fit or, even worse, hinder your progress. Recognizing red flags early in the hiring process can save you time, money, and frustration.

That's why Business Insider asked Dr. Susie Spirlock, a doctor of physical therapy and strength-training coach at Move Your Bones, and Ashley Hiben, a certified personal trainer at Future, what red flags to look for when hiring a personal trainer.

Here's what they said.

A trainer should have practical experience in the field

Practical experience provides personal trainers with invaluable opportunities to build relationships, hone communication skills, and translate technical expertise into accessible guidance, Hiben told BI.

"Time in the field sharpens a trainer's ability to read body language, adapt communication styles, and generate energy and engagement in various environments," she said. "Trainers who gain hands-on experience, whether at a small personal-training gym or in larger groups, learn critical skills beyond the textbook."

Hiben added that some of these skills include reading body language, identifying proper alignment in individual movement patterns, and responding in real time to verbal and non-verbal feedback.

"A robust field experience cultivates the balance between technical knowledge and the ability to connect effectively with clients," she said.

"No pain, no gain" isn't a mantra any trainer should have

It's best to avoid working with someone who encourages you to push through pain while exercising, Spirlock advised.

"Pain is essentially a smoke alarm in your body being set off because there is something going on that may not be right," she told BI.

Although pain doesn't automatically mean there's damage occurring, it does mean that the trainer may need to reassess the exercises and make them more comfortable for you.

"If trainers continually ignore these signals or tell clients to push through them, they may contribute to a longer-lasting issue over time," Spirlock added.

Beware of instructors who lack communication and relationship-building skills

"In the fitness industry, trainers must excel at reading clients' needs, offering constructive feedback, and even giving a dose of tough love when needed," Hiben said. "It's not enough to deliver knowledge alone."

Hiben told BI that the most successful trainers are adaptable communicators capable of engaging each client based on their unique personality, fitness level, and goals.

Before committing to a trainer, she recommended first requesting a consultation or assessment.

"This session allows you to gauge whether the trainer's communication style aligns with your needs and whether they will push you in a way that feels supportive rather than confusing or intimidating," Hiben said.

Trainers shouldn't try to diagnose or treat pain

Spirlock told BI that diagnosing and treating pain doesn't fall under a personal trainer's scope of practice.

"This should be left to the rehab professionals like physical therapists, chiropractors, and athletic trainers," she told BI.

If you have pain that's not improving after a few sessions with modifications, Spirlock said it's the trainer's responsibility to refer you to the appropriate provider.

She told BI that a highly qualified personal trainer will already have rehab professionals within their network, so they can work together to help you alleviate pain and meet your fitness goals.

Make sure your instructor can explain why they chose a certain exercise

The point of hiring a personal trainer is to get customized workouts that fit your long-term health goals. Therefore, every movement should have a purpose behind it.

"In the world of fitness, there should always be a reason as to why we choose exercises for a client," Spirlock said.

If a trainer can't explain to you the intent of an exercise, then they may not be considering your goals or have enough experience with designing personalized workouts.

A lack of empathy or an ego-driven approach are immediate red flags

"Empathy is non-negotiable," Hiben said. "Trainers who can't sense when to support a client during tough times risk losing the trust that underpins successful coaching."

Stress, for example, impacts the body's ability to function optimally. When trainers recognize signs of stress, they should adjust their workout plans accordingly and offer encouragement instead of push clients beyond their current capacity.

Similarly, a rigid, ego-driven approach can stifle both individual and team growth.

"Trainers with an inflated sense of expertise are often resistant to feedback, limiting their own development and potentially disrupting team dynamics," Hiben said. "Given that exercise science evolves, humility and openness are invaluable traits in a trainer."

Instead, Hiben said to look for trainers who are experienced, open to feedback, and empathetic.