There are many proven physical and mental health benefits to regular physical activity.

"From my perspective, the positive impact on mental health is one of the best health benefits of physical activity," Chloe McLeod , accredited practising dietitian and sports dietitian, told HuffPost Australia.

"When you're physically active your body releases more hormones which can help with improving mood, particularly serotonin, the 'happy' hormone."

Then there are the physical benefits of exercise.

"Other than that, exercise is good for cardiovascular health, can help improve metabolism, manage weight, manage blood sugar levels, reduce inflammation and manage stress. There are so many different benefits.

"And it's free. If you want to spend money on a gym or a class, go right ahead. But you don't have to."

If you are regularly physically active, you may:

• Reduce your risk of a heart attack
• Manage your weight better
• Have a lower blood cholesterol level
• Lower the risk of type 2 diabetes and some cancers
• Have lower blood pressure
• Have stronger bones, muscles and joints and lower the risk of osteoporosis
• Lower your risk of falls
• Recover better from period of hospitalisation or bed rest
• Feel better – with more energy, a better mood, feel more relaxed and sleep better.

Source: Better Health Channel Victoria.

The exact amount of times or minutes you should exercise per week depends on factors like your body composition goals, training background, age and overall health status, but there is a guide we should aim for.

"For any individual, doing some physical activity is better than doing none," Jessica Spendlove, accredited practising dietitian, accredited sports dietitian and nutrition consultant, told HuffPost Australia.

If you're currently doing no physical activity, start by doing some exercise and gradually build up.

"The Australian guidelines recommend we accumulate 150 to 300 minutes (2.5 to 5 hours) of moderate intensity physical activity, or 75 to 150 minutes (1.25 to 2.5 hours) of vigorous intensity physical activity, or an equivalent combination of both moderate and vigorous activities, each week," Spendlove said.

"They also recommend doing muscle strengthening activities on at least two days per week."

If your goal is to lose weight, Spendlove recommends aiming for the upper end of the scale.

"If you are training for an event or competition then you will need to do conditioning and resistance training specific to that event."

And don't forget about incidental exercise like gardening, cleaning and walking to the shops, which can quickly add up throughout the week.

"Get off the train or bus a stop early and walk the rest of the way," McLeod said.

"People feel like exercise has to be really big sessions, but it's just about doing your best to incorporate some rather than none, particularly at the starting point.

"Find what you like doing. Maybe you don't like running but enjoy swimming -- you could go swimming for half an hour three times a week. Then suddenly you've met your vigorous intensity physical activity guidelines."

Although many Australians don't exercise enough, for those who exercise frequently or intensely, it is certainly possible to overdo it, which can compromise your results.

"There definitely is such thing as too much exercise," Spendlove said. "Each individual will have an individual threshold for what constitutes too much exercise."

For some people, particularly athletes, exercising in excess of the guidelines may just be part of their program.

"It needs to be taken on an individual basis. As an example, I work with a lot of triathletes, so people who are doing Ironman and 70.3 events, and they're training 15 plus hours per week, which is obviously well in excess of what the guidelines are. But if those individuals weren't doing that levels of training, they wouldn't be able to participate in their sports," McLeod said.

"However, for others that would be too much exercise, so it's about looking at how fit the individual is, what their goals are, how they're fuelling their body for the training they're doing, and what their medical history is."

For instance, people with eating disorders will have a different exercise threshold to others.

"If someone has anorexia nervosa or another eating disorder, then you'd also want to look at what exercise they're doing and how much they're doing it more closely, and the exercise guidelines might change."

While there's no one answer to 'how much is too much exercise', there are distinct signs you may experience.

"Over-exercising can cause an energy imbalance (between the amount of energy consumed and the amount of energy expended during exercise). If you're in an energy deficit for an extended period of time it can cause many health issues," Spendlove said.

"Too much exercise can lead to injuries, exhaustion and hormonal imbalance."