Andy Devaney
If you’ve ever opened the internet to “learn fitness” and emerged an hour later convinced you need to sprint daily, lift nothing heavier than a water bottle, and sweat like a sauna or it “doesn’t count”, welcome to the modern age of gym myths—where confidence is high, evidence is optional, and everyone’s cousin is a strength coach.
PureGym’s fitness experts are attempting to tidy up the mess. A new poll of 149 PureGym managers has revealed the most common training misconceptions they hear on the gym floor from UK gym-goers—ideas that sound plausible, spread fast, and quietly derail progress.
The most common gym misconceptions (according to 149 PureGym managers)
- Cardio is the number one way to lose weight: 71%
- Lifting weights will result in a bulky physique: 71%
- Women should do different exercises to men: 43%
- Not feeling sore means you didn’t get a good workout: 34%
- If you don’t sweat you didn’t work out properly: 20%
- You shouldn’t do cardio on the same day as weight training: 8%
In other words: the greatest hits of misunderstanding, on repeat—fuelled by social media soundbites and the old British tradition of mistaking “hard” for “effective”.
Cardio is the number one way to lose weight (71%)
Why do we believe it? Cardio is accessible, it feels like you’re doing “proper exercise,” and it undeniably burns calories. Compared with lifting weights, a jog can look like the quicker route to weight loss—especially if you’re still worried the dumbbells are secretly a one-way ticket to Hulk City.
Why isn’t the myth true? PureGym Insider Kay says: “If your goal is weight loss it’s important to remember that you will likely not only be burning fat but losing muscle mass too. By including weight training in your routine alongside cardiovascular activities you can help to offset the rate of muscle mass loss.
Your muscle mass can influence your basal metabolic rate, which influences how many calories you naturally burn at rest. Therefore, although cardio does appear superior to weight training in regard to initial calories burned, weight training has been shown to increase the calories burned after an initial exercise period. Plus, weight training also provides lots of other health benefits that you may not get from cardiovascular exercise, such as improving strength and bone density.
Ultimately weight loss is dependent on energy balance. You need to be in an energy deficit to lose weight. Other elements like nutrition, recovery, sleep can impact weight loss so these should also be considered.”
Translation: cardio is useful, but it’s not a magic eraser. If you want the scale to move while keeping your body capable, strength work belongs in the conversation.
Lifting weights will result in a bulky physique (71%)
Why do we believe it? Because “bulking” is a word that gets lobbed around like confetti, and many people assume weight training equals size—full stop. Add in a few misleading before-and-after photos and suddenly everyone thinks a beginner dumbbell session comes with an automatic bodybuilding subscription.
Why isn’t the myth true? PureGym Insider Marni says: “Despite the growing popularity of females’ weight training, I still find many females worry about this, but science shows that women do not have the same testosterone levels to build the same amount of muscle as men. Building muscle doesn’t happen overnight.
Beginners may initially have the advantage of building muscle at a faster rate than experienced lifters (also known as newbie gains), but they will often see the rate of growth slow down as they become more experienced.
If you’ve noticed just after working out in the gym that the body parts you’ve worked feel larger, this feeling can often be mistaken for being muscle gain but is usually a result of blood being pumped to the area. This usually wears off about an hour after training and is most likely not a change in muscle mass.”
So yes, weights change your body—but “accidentally bulky” is largely one of those gym myths that refuses to die.
Women should do different exercises to men (43%)
Why do we believe it? Because men and women aren’t identical physiologically, and it’s easy to leap from “different” to “must train differently”. Fitness marketing has also done a spectacular job of selling “men’s workouts” and “women’s workouts” like shampoo.
Why isn’t the myth true? PureGym Insider Kay says: “While men and women may have different preferences on which body parts they want to focus on and train, our genetic makeup is the same (we’re humans after all) so I don’t see why women and men should have to perform different exercises. The exercises you choose should be based on your personal preference, needs and goals and not be defined by your gender.”
Best rule: choose exercises that match your goals, your body, and your schedule—not your stereotype.
Not feeling sore means you didn’t get a good workout (34%)
Why do we believe it? Because soreness feels like proof. It’s the body’s receipt: “You suffered, therefore it worked.” The problem is, soreness is a signal—but not a scoreboard.
Why isn’t the myth true? PureGym Insider Sky says: “Muscle soreness comes from microtears in muscle, mostly from new exercise or stimulus. You will usually feel a lot of muscle soreness when starting a new programme or exercise regime as your body is pushed beyond what it is used to.
These microtears are necessary for your muscles to grow but require adequate rest and nutrition for your body to repair and re-build your muscle fibres. The stronger you get and the more your body adjusts to the new stimulus, the less soreness you will experience so that’s not to say you didn’t get a good workout. You shouldn’t be feeling sore after every workout and you certainly shouldn’t feel pain.
There’s a fine line between challenging yourself and hurting yourself, so make sure to find that right balance.”
In grown-up terms: progress is measured by performance, consistency, and recovery—not how you walk down stairs the next day.
If you don’t sweat, you didn’t work out properly (20%)
Why do we believe it? Sweat is visible. It’s dramatic. It makes you feel like a warrior. Unfortunately, it’s also heavily influenced by temperature, clothing, genetics, hydration and fitness level—none of which are reliable judges of workout quality.
Why isn’t the myth true? PureGym Insider Sky says: “Sweating is just a response to an increase in your core temperature and is your body’s way of cooling down. Some people may naturally sweat more than others and some people may find they don’t sweat much, so it isn’t necessarily a measure of how hard you worked.”
Sweat is a cooling mechanism, not a merit badge. File that under gym myths and move on.
You shouldn’t do cardio on the same day as weight training (8%)
Why do we believe it? Because some research suggests that combining both without proper recovery can blunt certain adaptations. People hear “interference effect” and interpret it as “never mix them,” as if your body can’t cope with more than one idea per day.
Why isn’t the myth true? PureGym Insider Kay says: “It’s okay to perform cardio and weight training on the same day, as long as this is based around your needs and goals, but give yourself enough time to rest and get adequate nutrition.
There are athletes and gym goers who do cardio and weight training on the same day. Ultimately, how you train, and your exercise selection should be based around what’s best for you and your goals.”
The sensible takeaway: you can mix sessions—just do it with intent, and recover like you mean it.
Practical takeaway: what to do instead of believing gym myths
- Build your week around goals: fat loss, strength, fitness, sport, health—pick the priority.
- Combine strength + cardio: not as rivals, but as teammates.
- Track progress properly: reps, load, pace, consistency, sleep, energy—more useful than soreness.
- Recover like it counts: because it does—nutrition, rest, and enough training days you can actually sustain.
Because the truth is boring, but effective: consistency beats chaos, and evidence beats folklore—every time.
