The other half ‘go through the motions’, usually because they are there to look at the opposite sex, don’t know how to use the equipment or simply don’t want to sweat.
The study also found that the 50 per cent of gym users who don’t take the workout seriously, spend the majority of their visit chatting with friends and reading.
One in four even owned up to spending more time relaxing in the sauna or hot tub than the exercise machines.
Additionally, one in ten said they like to ‘chill-out’ around the pool and watch music videos and one in 20 said they head to the gym to watch football on a big-screen TV.
Is it any wonder then that nearly two-thirds of gym members claim to not make the most of their subscription.
A spokesperson for home sports equipment firm Kettler, which commissioned the research, said: ”It appears not all gym users are making the most of their time at the gym.
”There seems little point in paying high membership fees if you are not making use of your time at the gym.
”Some gyms fees can cost up to £2,000 a year which is a huge amount of money to shell out, especially if you are reading whilst on the treadmill or cross-trainer.
”Whilst you need to warm down and chilling around the pool is great, it does seem a little pointless paying for the use of hi-tech machines if you are not using them properly.”
The research also revealed one in ten fitness enthusiasts said they only joined the gym to meet the opposite sex. And ten per cent signed-up because it was ‘the trendy thing to do’.
Furthermore, one in 20 only go to the gym because it’s part of their benefits package at work.
More than half of the 2,000 gym goers polled said they don’t do extensive workouts and 29 per cent said they never break a sweat.
In fact nine per cent said they would be embarrassed if they did start to sweat.
Women were the worst offenders amid concerns their make-up will smudge or their hair will frizz if they perspire too much.
Forty per cent of respondents said women were most guilty of not using the gym for a proper workout.
More than one in ten said they were too self-conscious to do a proper workout and didn’t want others looking at them.
But 39 per cent said they weren’t sure about how to use some equipment so didn’t want to look stupid.
A spokesman for Kettler added: “It’s understandable people feel self-conscious at the gym, especially if you have joined up to lose a large amount of weight.
“It can be intimidating standing next to really toned bodies or hardcore fitness fans, especially if you are unsure of how to operate equipment.
The study also found that 29 per cent of people head to the gym just to get out of the house.
But a crafty 13 per cent claim they are off the gym, when in actual fact they go somewhere else entirely.