Workout mistakes to avoid making if you're new to exercise, whatever your age

Workout mistakes can stop you making progress. Here, two personal trainers explain how and what you can do about it

Woman lifting dumbbell above her head in the gym after learning about the top workout mistakes
(Image credit: Getty Images)

Workout mistakes can be the difference between making progress in fitness and stopping at the first hurdle for many people. While some of them are simple and relatively easy to fix with few long-term side effects, others can lead to injuries that will keep you away from whatever exercise you enjoy. 

When we start working out, we all make mistakes. It’s the most common part of taking up any sport. It could be wearing the wrong clothes or shoes, not having the right equipment or technique, or just not going for long enough to really feel the benefits of the movement. 

Whether your favorite exercise is LISS cardio, swimming lengths in the pool, or nordic walking in the countryside, we’ve got personal trainers and coaches on hand to lay out the biggest workout mistakes people make at different ages.

Why do workout mistakes happen?

The most common workout mistakes come when trying to build a fitness regime yourself, says Freeletics (opens in new tab)’ training and nutrition specialist, David Wiener. That’s not to say that someone with a personal trainer wouldn’t be making these errors in their own time, but creating your own workout routine from scratch can lead to some challenges - especially if you’re new to exercise. 

“Making that first foray into the gym can be a daunting one,” agrees Aroosha Nekonam, certified personal trainer at Ultimate Performance (opens in new tab). “When you hit the gym floor, it may be overwhelming to see the array of machines and equipment on offer and wonder what you should do.”

Whatever your age, some workout mistakes are easily avoidable. These are the experts' top picks…

What are the biggest workout mistakes?

1. Not warming up

We’ve been taught to warm up before exercise ever since P.E lessons at school. But it’s easier said than done if you’re feeling limbered up and eager to get out to your session or feel like you don’t have the time before your workout. 

It’s one of the top workout mistakes that trainers see often, David says. “Most of us are guilty of skipping a warm-up, thinking they’re pointless or part of your workout which can be skipped. This couldn’t be further from the truth. A warm-up before working out is absolutely essential and can be the difference between achieving a personal best or avoiding an injury.” 

“In truth,” he says, “You need to prepare the body before exercise so your muscles aren’t tight, to improve circulation and muscle elasticity. Not only does this lessen the risk of injury, but it will also improve your range of motion, effort, speed, and strength.”

Aroosha agrees, “Spending 10 to 15 minutes a day on mobility and flexibility will pay huge dividends when it comes to staying healthy as you age. For clients in their 40s and 50s especially, this is critical. The ability to ‘get away with’ poor posture and technique diminishes, so the need to be warm and pliable before and during training is enhanced.”

For best results, according to a review by sports rehabilitation specialist Dr Phil Page (opens in new tab), anyone doing flexibility-based exercises such as yoga for beginners or dance should do static stretching (where you don't move) after an active warm-up and anyone opting for more power-based workouts should exclusively do dynamic movements, like stretching for runners. This, the American College of Sports Medicine says, should be done two to three days a week in four rounds. 

Woman making smoothie with bananas and nuts in a blender at home to combat the biggest workout mistakes

(Image credit: Getty Images)

2. Not eating enough

Exercise can only get you so far if you’re looking to make changes, whether that’s in how you look or how you feel. “If you have a poor diet, you will not be seeing the results you want,” David warns. “When it comes to strength training, your muscles need to be fed so that they can replenish and repair, helping to enhance strength or size.”

In your 40s and the early stages of perimenopause symptoms, starting resistance training is particularly important as the gradual decline in hormone levels slowly reduces muscle mass. But as does not eating enough, and the two combined are a recipe for disaster. 

“Diet is the most essential component of any fitness journey, and should never be overlooked, no matter what your goal. Eating a well-balanced diet which contains protein, carbohydrates, and healthy fats is key,” David suggests. 

This is certainly something to be aware of if you’re trying to lose weight as well, Aroosha says. “Unfortunately, there’s no such thing as a fat loss food. But the good news is that there are not any truly fattening foods either. Some foods are just more nutritionally dense and support our physiology and health better than others. Some keep us feeling fuller than others, but no food alone will make us gain weight unless we overeat them.”

You’ll indeed need to be in a calorie deficit to lose weight but cutting out whole food groups or staying away from your favorite meals in favor of ‘healthier’ choices won’t work. “For example, carbohydrates do not inherently make you gain weight. Fats don’t and neither does sugar, outside of a calorie surplus. For food to be fattening, it would have to cause us to store body fat regardless of our energy balance. It would also defy the laws of thermodynamics.”

She adds, “That is not to say that food choices are irrelevant. It simply highlights the fact that it is energy balance that is the most important factor for fat loss success, however, we may achieve that.”

So instead of not eating enough food, Aroosha recommends adding things to your routine like more daily activity, more nutrient-dense foods, and improving your sleep while lowering stress levels. If following a rule when it comes to eating works for you, the 80/20 diet rule proposes eating nutrient-rich foods most of the time and more indulgent foods in limited amounts. 

3. Not drinking enough water

“As a rule of thumb, wherever or however you are choosing to work out, always bring a drink with you,” David says. “Being dehydrated when training can noticeably decrease your muscle performance and put an early end to your workout.” 

This is because drinking enough fluids lubricates your muscles and your joints which will make a workout much more effective and efficient. “Not only this,” he says, “While you work out, you’re raising your body temperature and losing fluids through sweat, so you need to replace them straight away to be able to keep going. 

As well as being one of the biggest workout mistakes, not doing so can be particularly dangerous, research from Loughborough University (opens in new tab) found. They discovered that exercise in warm conditions, whether that's outside in the heat or just in an under-air-conditioned space, and a lack of replacement fluids was associated with reduced stroke volume, lower cardiac output, and decreased blood flow to the muscle.

"Water will always be a top choice, but whatever you chose to drink is better than no drink at all," David says. 

Woman doing yoga in the park on blanket in the sunshine

(Image credit: Getty Images)

4. Not mixing up your exercise routine

“Everyone is guilty of sticking to a routine and sometimes it’s not a bad thing,” David says. “Of course, it’s good to have a plan when it comes to your workout and finding out what you like to do and what you don’t.” 

But for the ultimate results, he suggests, step out of your comfort zone. “When you are repeating what you do every week, not only will it become boring, but it can cause injury due to you putting repetitive stress on the same muscles.”

It may be a stereotype but it’s unfortunately true that women are more prone to this than men with fewer taking up strength training alongside cardio, a study by the University of Northern Iowa (opens in new tab) says. “There is a common belief that women should only use cardio as a means of fat loss and healthy weight management. Whereas, weight training is the preserve of men. Anxiety about stepping into the weight room, fears that weight training makes women bulky, and believing cardio is a must for building a physique are all factors that hold women back,” Aroosha says. If this is how you feel, enlisting the help of a personal trainer could boost your confidence in the gym. 

“Keep the excitement in your routine by mixing it up, like alternating between walks, gym, yoga, and using workout apps from the comfort of your own home,” David adds. 

5. Not doing full body training

Similarly, many of us will focus on just a few parts of the body. “Upper bodywork is, unfortunately, something a lot of women neglect in their workout routines, usually because the first thing that comes to mind is female bodybuilders,” Aroosha explains. 

This is a look that some people spend years of their life trying to build, so it’s unlikely you'd get there accidentally. Some women also don't naturally produce as much testosterone as men, a report from the University of Sydney (opens in new tab) explains, which is a huge factor when it comes to growing significant amounts of muscle. 

“While this is not only a myth, the lack of training your upper body can prevent you from building the feminine figure you truly want,” Aroosha explains. “Building a strong, balanced, and athletic physique means training your whole body, so there is every reason you should incorporate upper body exercises into your training regimen."

Woman working out with personal trainer, lifting weights in gym studio

(Image credit: Getty Images)

6. Lacking proper form

This one’s mainly for the gym-goers and garden weightlifters out there but it's one of the biggest workout mistakes that can apply to runners and cyclists too. “It’s important to know that an exercise is most beneficial if you’re doing it correctly,” David says. 

“Form, technique, and posture are essential to be able to see results. Engaging the correct muscles will help you progress on your fitness journey, rather than halt it. Doing some research into the exercises you’re doing or getting guidance from a trainer could be the difference in rapid results or a fitness plateau.”

When it comes to strength training specifically, “doing an exercise half-heartedly or not using the correct form will not be strength training efficiently," he notes. 

7. Spending too long working out

As much as many people tend to not do enough exercise, some do too much. The physical health benefits of working out are famous - but so are the mental health ones. It’s very easy to get wrapped up in the endorphin rush of a 10k run or the serotonin surge from an exercise class and end up overdoing it. 

“During intense and long-duration exercise, [a stress hormone called] cortisol is produced,” Aroosha explains. “To produce a positive, adaptive response to exercise, cortisol is necessary and very beneficial. Through resistance training in particular, the rise in anabolic hormones in combination with cortisol provides a very healthy beneficial response, whereby the body will work to lose fat and build muscle.”

In your 20s, 30s, and early 40s, overdoing it means struggling with delayed onset muscle soreness (DOMS) for a few days, along with potentially other symptoms like tiredness, fatigue, and an increased appetite. It's not going to be too serious for most people, concludes a review by the Hospital of Lithuanian University of Health Sciences (opens in new tab). But when it comes to the 40s and early 50s, things change. 

"Particularly with menopausal clients, the devil is in the detail," Aroosha says. "As we know, there is a decline in the ovarian production of estrogen and progesterone, which act as controls for cortisol and insulin. It is often the case that women in this stage of life will be stress-sensitive and this should be factored into their exercise regime."

Shorter, intense bursts of exercise will be more beneficial for those going through any of the stages of menopause, she explains, as will "weight training, high-intensity interval training, metabolic conditioning, and limiting workouts to no more than 45 to 60 minutes."

But for menopausal women, the act of balancing the 'yin and yang' is often undervalued too, Aroosha says. "This means also including relaxing active activities such as walking, yoga, Tai Chi, meditation, and different types of massage. By creating a smarter stress-inducing exercise regime, you can help stir menopause physiology to work in your favor."

9. Not stretching after working out

“If you work out and don’t cool down, much like if you don’t warm up, you are not helping your body recover,” David says, pointing out one of the most common workout mistakes people make. “Often we overtrain and then fail to rest and recover, giving our bodies little chance to heal.” 

This especially happens to those who do a little too much exercise and normally exercise at some intensity every day. While the NHS says that 150 minutes of exercise per week is optimal, how much exercise to do per week is different for everyone. As fitness and nutrition coach David explains, “Rest days are extremely important, and they will not hinder any progress you have made despite what people may think. They will actually optimize your performance and get you ready for the next time you train.” 

If you’re mainly training in the gym or doing HIIT workouts for instance, where you can optimize them to train particular areas of the body, and you’re training one day after the next then you need to also reconsider how you train. “When you’re training one day after another, I would recommend muscle splits," he adds. "Muscle splits is where you train certain muscle groups on alternative days, resulting in time for your muscles to recover in-between sessions, even if you’re training others.”

However, with all of this in mind, both the experts agree that doing any exercise - even with some of these mistakes - is better than no exercise at all. “Looking after your body as you age into your 40s, 50s, and 60s is very important. So first of all, give yourself credit for taking that important first step towards looking after your body and your overall health,” Aroosha says.

Grace Walsh
Grace Walsh

A digital health journalist with over five years experience writing and editing for UK publications, Grace has covered the world of health and wellbeing extensively for Cosmopolitan, The i Paper and more.


She started her career writing about the complexities of sex and relationships, before combining personal hobbies with professional and writing about fitness. Everything from the best protein powder to sleep technology, the latest health trend to nutrition essentials, Grace has a huge spectrum of interests in the wellness sphere. Having reported on the coronavirus pandemic since the very first swab, she now also counts public health among them.