Health & Fitness, Fitness & Training

How do I get my energy levels up?

To be fit and always have enough energy to do what you love, pay attention to your diet, breathe well, exercise and get enough sleep. These 4 tips may seem simple, but what is the scientific basis for them? Learn more about how energy metabolism works and put in place a winning strategy to optimise your performance and quality of life.

Balancing your energy supply

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Calories are a unit of measurement for energy. If you don’t get enough calories from your diet, your body will use its reserves to perform the tasks you are asking it to do (exercising, of course, but also digesting, thinking, etc.). Naturally, you will lose weight, but you will be tired, and your muscles will weaken. Too great an energy deficit can seriously impair athletic performance and quality of life. Conversely, eating more calories than you need can lead to weight gain. Moving around when you are overweight requires more energy than when you are at your ideal weight: for a given effort, an overweight person will tire more quickly.

Not all nutrients provide the same amount of energy (and especially the same quality): for example, for the same amount of calories, fat will fill you up less than carbohydrates. Foods rich in protein, on the other hand, are satiating. The carbohydrates, fats and proteins consumed can either be used or stored (e.g., as fat).

A nutrition tracking application allows you to ensure that you have a balanced energy supply. Depending on your age, height and weight, you will be given an estimate of how many calories your body needs at rest. Enter what you eat to find out how many calories your body receives each day and how these are distributed. At the same time, track your energy expenditure for the day to see if you are doing the right amount of exercise and eating.

Breathing well: Oxygen is essential for good performance

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Producing energy is the primary role of oxygen. Muscles need oxygen to contract. At the cellular level, small structures called mitochondria convert nutrients into energy for the body in the form of ATP molecules. Learning to breathe well and engaging in endurance exercises to optimise cell oxygenation are effective strategies for making better use of energy.

Sleep well to recharge your energy and repair your body and mind

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You already know that the body regenerates and regains strength during the night. Recent studies show that sleeping well also helps to manage energy expenditure, allowing the body to do more with less. Scientists hypothesise that this better allocation of resources may be taking place during REM sleep. Indeed, the body has difficulty maintaining its temperature during this dream phase when the brain is very active. Thermoregulation is one of the most energy-intensive processes in the body. The more you sleep, the more you make use of this built-in energy-saving feature, which is at work for about 20 to 25% of your nights! 


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Having more energy is an excellent reason to start exercising: by improving your cardiorespiratory capacity and physical condition, you start a virtuous cycle. The contraction of muscles during physical activity has a vasodilator effect: to meet the increased oxygen needs of muscles and organs, blood vessels dilate, and blood flows better. By being active, you take in more oxygen and keep your body in good working order. Nutrients are better distributed, and you also improve the quality of your sleep.

By building muscle, you increase your energy expenditure, even at rest: you don’t store as many nutrients in the form of fat. You use what you eat quickly when you need to exert your body. As always, balance in all aspects of your life is key.

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