The middle-aged spread, a snail’s-pace metabolism and declining muscle tone once seemed like inevitable waymarkers of the midlife years.

But recently they have been replaced with the notion we can stay fit, toned and healthy for longer than ever. And in many cases, we might be fitter after 40 or 50 than we were during our (misspent) youth. ‘Ageing is inevitable,’ says personal trainer Christina Howells, 50, co-founder of That Girl online training programmes. ‘But declining health and fitness doesn’t have to be. Being fit to do all the things you want to do has less to do with your actual age and more to do with how you lead your life.

‘And it’s even easier at this time of year, when the days are longer and lighter and you can get out and be more active. Reaching your 40s and 50s is no longer a time to throw out your trainers and resign yourself to an expanding waistline, but rather an opportunity to shift your mindset - if you haven’t done so already - and join the emerging new breed of 40- and 50-somethings who are celebrating ageing and making it work for them.”

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From Bollywood’s Madhuri Dixit (51) to Jennifer Aniston (49) to English TV presenter Davina McCall (50), images of celebrities with “ageless” bodies have become – commonplace – so what’s behind the boom? Your 40s and 50s are typically a time when you have a little more free time – and resources – than you did in your frazzled, child-rearing 30s.

It can also be a decade of growing self-acceptance and confidence, and of greater awareness of health and well-being. Or, as 45-year-old Cameron Diaz, an ageless body proponent if ever there was one, recently said, ‘I know so much more about my body and how to nourish it now than I did when I was 21.’

‘Your 40s and 50s can be a great time to finally make peace with your body, rather than constantly being unhappy with it and fighting to change it,’ says Howells.

‘This summer fitness plan isn’t about that, but rather looking after your body, and respecting that it’s your vehicle for life. Just a few small changes will show results within weeks.”

Why we need to move more

‘Our bodies weren’t designed to stand on escalators, sit at desks all day or use machines for our daily tasks,’ says Howells. ‘Yet so many of us do those things, and the older we get, the more we tend to slow down and move less. But all movement is medicine, so use your muscles at every opportunity.

‘Walk as much as possible, carry heavy shopping bags, where possible walk or cycle instead of driving, and arrange family activities that get you all moving. Even if you go to the gym twice a week, don’t spend the rest of the time sedentary.

‘I once trained a 60-year-old man who wasn’t particularly into my mobility exercises. He said to me, ‘Look, I just want to look good on the beach.’ But I explained he wouldn’t even be able to get out of his deck chair if he didn’t take care of his mobility.

As we age, our joints do, too, so to avoid injury and having a creaky body that can’t get out of a chair with ease, it’s important to do mobility exercises. They’ll reduce your risk of injury, too.’

Start at a lower intensity

‘If you’re new to exercise – and I see plenty of 40 and 50-somethings who have never really exercised, but who come to me wanting to get in shape in these decades – then low-intensity cardio is the best place to start,’ says Howells. ‘Walking, gentle jogging, swimming, gardening, or stretch classes such as yoga and Pilates, are good options.’

What about cardio?

‘As well as strength and mobility, cardiovascular exercises like running and cycling are fantastic and reduce our risk of heart disease, high blood pressure and diabetes, the risks of which increase with age,’ says Howells.

‘Cardio is also excellent for boosting energy levels and mood. I’m a big fan of HIIT (high intensity interval training) exercise, providing you have no medical problems or injury,’ she says. ‘HIIT is a fast-paced routine that alternates between a short burst of intense aerobic exercise, such as sprinting, power walking, cycling or completing prescribed moves such as burpees at full speed, followed by a brief lower-intensity period. This pattern is repeated, usually for about 15 to 20 minutes.

‘Briefly pushing your body to the max, letting it recover, then pushing it again, helps improve cardio and respiratory health, reduces body fat and controls glucose levels. Still, HIIT is not for every day and I would recommend one to two HIIT workouts a week, with plenty of time for recovery.’

The Ageless Body mindset

According to Howells, managing sleep and stress are just as key to achieving an ageless body as exercise and eating well. ‘What you’ll find with stress, eating and exercise is that they’re intrinsically linked,’ she says. ‘If you sleep better, you’ll feel less stressed during the day and you’ll make better food choices. If you exercise, you’ll sleep better. If you’re sleeping, eating and moving well, you’ll feel more able to handle stress. And so on.

‘Hormonal changes can work against you, but they’re a natural part of ageing and can be countered. Testosterone decreases in both men and women, as does oestrogen in women, and both slow down exercise recovery. In pre- and menopausal women, fluctuating oestrogen can cause crashing fatigue, where exhaustion hits them quite dramatically out of the blue and leaves them feeling wiped out. So it’s not always the time for excessive training. As ever, listen to your body and do what feels good and right.

‘In your 40s and 50s, take a more holistic approach to exercise and be more body-aware; your body needs adequate rest and sleep, more than ever as you get older. And this may mean building more rest days into your weekly exercise schedule as well as varying training intensities throughout the week.

‘Men and women in their late 30s, 40s and 50s are often quite successful and busy in their careers, running a business or managing a team of staff. They may be worrying about ageing parents, or teenagers doing exams. There’s a lot to ruin your sleep at this age, plus they may have built up sleep debt from the child-rearing years and picked up poor sleep habits.”

Ageless eating

Our 30s, 40s and 50s are often a time we eat due to boredom, stress, ingrained habits or other emotional factors, says Howells. ‘Having the odd bit of cake or chocolate is nothing to worry about. But if you’re regularly eating in a way that makes you feel unhealthy, or snacking when you’re not even hungry, then you need to think about what’s going on,’ she says.

‘Questioning your eating habits is often more helpful than just banning certain foods or trying to diet in the traditional sense. Try to break food associations, like chocolate in the afternoons, snacking when you’re on deadline and so on. Try to be more mindful of what and why you’re eating.’

Another key is to keep in mind your blood-sugar levels, she adds. ‘Blood-sugar balance is a good place to start, because it helps with sugar cravings, tiredness and energy slumps. So avoid sugary foods and drinks and you’ll quickly notice the difference it makes to your body and energy levels.

‘Eat plenty of good fat, too. Hormones such as oestrogen and progesterone are actually steroid hormones that are derived from cholesterol. 
This means that in order for them to be created, you’ll need to consume fat and cholesterol on a regular basis. Additionally, since having higher levels of these hormones is associated with an increased amount of fat metabolism, it makes sense that you should have a higher intake of fat in your diet. So eat oily fish, nuts, seeds and oil, alongside eggs, lots of vegetables and fruit.’

Tips for better sleep

✱ Don’t snack at night: especially on sugary snacks that are stimulating and will disrupt sleep. The same goes for too much alcohol.

✱ Power down: At least an hour or two before bed put your phone away. Yes, you’ve heard it before, but yes, you’re still not doing it! Like any health change, start slow and build up.
✱ Don’t chase sleep: the less you think or worry about it, the easier it comes.

✱ Exercise: a study from the University of Georgia in the US found that sedentary adults who began exercising moderately three times a week felt 65 per cent less fatigue after six weeks.

✱ Keep your bedroom dark, quiet, and between 60 and 70F (16-21C).