Whether you prefer to focus on press-ups, pounding the pavement or perfecting yoga poses, you'll know there's no one-size-fits-all approach to fitness, no foolproof formula and definitely no shortcut to success.
Or is there? According to Dr Michael Mosley, British medical specialist and author of The Clever Guts Diet, scientists are discovering how we can get maximum benefits from our workouts – and some of the results might surprise you.
In his new TV show, The Truth About Getting Fit, Dr Mosley reveals his latest findings on how long our exercise sessions should be, which offer the most bang for your buck, and which you shouldn't bother with – and tells why standing on one leg can be the best indicator of our overall health. During a whirlwind visit to our shores, Good Health met up with him to get the lowdown.
Exercising little and often is best
If better aerobic fitness is your goal but lengthy jogs leave you cold, Dr Mosley says science has some good news. One of the most surprising findings from his latest research is that short bursts of intense exercise have a profound effect on heart and lung function, and you don't have to be an endurance athlete so see meaningful results.
"We did a test with a group of volunteers aged 25 to 45, where we put them on a stationary bike and after a warm-up, got them to do a 20-second burst of intense exercise, then have a small break, followed by another 20-second burst. The key is to really push yourself in those 20 seconds, and it needs to be done three times a week.
"After a couple of months, we saw big improvements in their aerobic ability, and the scientist leading the research said it would usually have taken 45 minutes of running three times a week to achieve similar levels of fitness."
Ditching those lengthy sweat sessions for just two minutes of exercise a week is an exciting prospect, and although testing is still in the early stages, Dr Mosley hopes the idea will encourage more people to exercise.
"We know that people lie hugely when they talk about exercise," he says.
"In the UK, about 40 per cent of people claim to do 150 minutes of mild to moderate-intensity exercise a week. But when you actually measure it, it's nearer to five to six per cent of people who get this amount, and I'm sure it's a similar case in this part of the world. Just telling people to exercise is pointless, but a lot of people would rather do 40 seconds than 45 minutes of running, including myself."
It's in (some of our) our genes to want to exercise
We all know that person who ticks off their list of completed marathons like items on a grocery list, and a gym bunny who skips to spin class every Saturday morning. But if exercise has never been your idea of fun, it's probably not your fault. According to this doctor-turned-journalist, it could be the result of genetics dating back generations.
"If you look at our hunter-gatherer ancestors, there was no incentive for most people to run," he says.
"If you were short on calories, you wouldn't want to waste them by going out for a jog. But some people in the group would have needed to go out and hunt, so the people who loved running would have been the ones to go off chasing the wildebeests. Most of the group would have sat around, or been busy collecting stuff and doing a few bits and pieces. This is what happens in society – you get people who love exercise, and a whole bunch of people who don't, and this is probably a reflection of our genetics."
Scientists call the lucky group who get the biggest high and most benefits from exercise the 'massive responders'. About a third of the population are thought to fall into this category.
Dr Mosley's studies led him to test a group of volunteers who love aerobic exercise and who reported getting the 'runners high' after pounding the pavement.
"We measured the level of a substance created in the body called an endocannabinoid, which mimics the effects of cannabis," he says.
"The level of this substance in these people's bodies shot up after running, and faded away after about an hour. Higher levels correlated very strongly with a positive mood."
There could still be hope for the rest of us too, in the form of new medication being developed that could boost the feel-good effects of exercise.
"It's a brand new science," says Dr Mosley. "But there are drugs now that can enhance the action of endocannabinoids. So it's possible that we might be able to take a drug to make us enjoy running."
Using exercise to train your brain
Think 'fitness' and you'd be right to conjure up images of resistance training and cardio workouts, but experts say there's a third and equally vital piece in the physical-wellbeing puzzle that most of us barely consider – balance.
"Stand on one leg with your eyes closed, and aim to hold it for at least 10 seconds," says Dr Mosley.
"This is linked to neurological strength. When you close your eyes and stand on one leg, there are two things keeping you upright: the balance sensors in your ear, and the proprioceptors, which [convey] messages from your muscles to your brain that tell you where you are in space. Messages move at high speed from the soles of your feet up to your brain and down again; the speed they move at is a measure of your neurological fitness. Wobbling as soon as you shut your eyes could be a sign they're not moving as fast as they should, but you can improve this with practise."
Many people turn to things like cryptic crosswords and Sudoku for brain training, but Dr Mosley, who also devised the popular 5:2 intermittent-fasting diet, says there's no evidence that they work. Exercise is the key, he says, and some forms of activity are better for your grey matter than others.
"Something that involves a combination of social, physical and motor skills has the best benefits for the brain. Dancing is particularly good as it includes the physical and social aspects, and a study found that salsa classes were the best as they also involve a complicated series of movements."
Find little bits of exercise to do
When it comes to life mantras, one of Dr Mosley's is simple: always take the stairs. In a world in which everything from shopping malls to offices are designed to direct you to the lift, this is no mean feat.
"At many of the hotels I stay in, the stairs are often really shitty – they're covered in grime, smell awful and are hard to find," says Dr Mosley.
"Whereas in Sweden, all the hotels have a great big fancy staircase, and the lift is round the back and really slow. I think this is why the Swedes are so slim. They've built fitness into their environment."
The final trick in Dr Mosley's exercise book? Try to have some fun with it.
"As humans, we're very tempted by the present, but not so tempted by the future," he says.
"The idea that something might be good for your brain in 20 years or your heart in 10 years is not a very seductive thing when you've got a comfy sofa and a great TV show about to start. That's why we have to find some immediate pleasure in exercise, like working out with a group of friends. Then you can go about making it a habit."