The quest to become fit in your 40s means that you must become a master at adapting to the whirlwind of change that life throws at you.

For some, relationships will go through challenges; for others parents need care-giving or pass away.

Routine medical check-ups may also bring to light a condition that will shape the way you treat your health for the rest of your life. You learn to accept the reality and adapt with the best strategy to manage your condition.

The changes to your physical well-being may start with the decline of your eyesight and hearing. You may be decreasing in height, your hair is greying and middle-age spread is starting as your metabolism continues to slow down due to the loss of muscle mass.

For many men trying to become fit in their 40s, this decade represents a time when they recognise a need to change their way of thinking about their health.

Years of neglecting exercise has resulted in a bulging belly and moobs.

Declining testosterone only speeds up this process.

Testosterone is the hormone that is necessary to build fat-burning muscle. In men of a certain age aromatization occurs, which is when testosterone converts into the female hormone oestrogen.

We know that lack of sleep, low intake of protein, lack of essential fatty acids like omega 3 and no weight training can lower testosterone, which is why men should do the opposite in order to slow the ageing process.

For females trying to become fit in their 40s, declining ovary function leads to greater fluctuations in hormone levels. The other big changes that happen are the menopause and, like men, declining testosterone function. For women this manifests as decreased libido, energy and sense of well-being.

When oestrogen levels decrease at menopause, women become more susceptible to osteopenia (low bone mineral density) but thankfully this can be counteracted with strength training.

Women who are worried about their bone density may take a calcium supplement. However this won’t be absorbed if they are lacking in vitamin D3.

The key to being fit in your 40s is to accept you are getting older but that you do not need to age as quickly as your peers. Eating fresh, healthy food, doing regular strength and interval training, taking a good multivitamin, sleeping regularly and taking time to recharge will all help you in the long run.