Cardio or strength training – which is better for your health?

Fitness beginners almost always start their training with the same debate. Some people are convinced that only jogging and cycling are suitable for health and weight loss. Others consider running a waste of time and send everyone to the gym to lift weights. This dichotomy creates the false impression that one must choose just one training approach. However, the physiology of the human body works differently. Our bodies need both cardiovascular training and strong muscles in equal measure.

The World Health Organisation provides clear clinical guidelines for adults. To maintain basic health, a person needs between 150 and 300 minutes of moderate aerobic activity per week, or between 75 and 150 minutes of vigorous physical activity. WHO experts explicitly state that strength training for the major muscle groups must be added to these aerobic sessions at least twice a week.

So the right question is quite simple. How can we sensibly combine these types of exercise and tailor them to our individual goals?

How the heart and muscles respond to different types of exercise

The body responds to a jog and to lifting dumbbells through completely different physiological mechanisms.

Cardio training causes large muscle groups to work continuously in a cyclical rhythm. This includes brisk walking, swimming, cycling, running and rowing. During such activity, the heart pumps large volumes of blood per unit of time. The walls of blood vessels become more elastic, whilst more mitochondria are produced within muscle cells. Mitochondria can be thought of as microscopic cellular power stations that supply tissues with energy and oxygen.

Scientifically established facts about aerobic exercise:

• Regular aerobic exercise has been proven to reduce the risk of developing coronary heart disease, high blood pressure and strokes.
• Cardio exercise improves the cells’ uptake of glucose and significantly reduces the risk of developing type 2 diabetes.
• Moderate-intensity aerobic exercise helps the nervous system cope with anxiety and promotes deeper sleep at night.

Strength training involves muscles overcoming the weight of an external object or the resistance of a piece of exercise equipment. You can do push-ups, squats, use resistance bands or work with heavy dumbbells. This type of exercise stimulates an increase in muscle fibre density, strengthens tendons and sends a clear signal to the skeleton to retain calcium in the bones.

Strong muscles are not just for looking good in the mirror. Muscle tissue serves as the body’s main store of glucose. After the age of thirty, everyone naturally loses between three and eight per cent of their muscle mass every decade. Strength training is the only reliable way to halt age-related muscle loss and protect bones from becoming brittle.

Weight loss and the real role of exercise in burning fat

Many people spend hours walking on a treadmill, watching the calorie counter. This device almost always overestimates by twenty or thirty per cent. An electronic sensor does not know your exact body composition or your actual fitness level.

The body loses weight according to just one rule: a person must expend slightly more energy in a day than they consume through food. Exercise merely helps to create this energy deficit, but it does so in different ways.

Gentle walking or swimming safely burn off excess energy. They do not put excessive strain on the knees nor cause intense hunger after a workout.

But if a person simply cuts back on food and runs endlessly, the body panics at the prospect of starvation. The body starts to shed muscle, because maintaining it takes up too many resources. As a result, the number on the scales drops, but the body becomes flabby and weak, and there’s no energy left for everyday life.

Strength training protects you from this trap. When you lift weights, the brain receives a direct signal: the muscles are needed for hard work and must not be touched. The body maintains a toned physique and uses only stored fat to cover the calorie deficit.

The formula for staying in shape is very simple. A small calorie deficit triggers weight loss, strength training preserves muscle, and cardio strengthens the heart and gently increases energy expenditure.

Does cardio hinder muscle strength gains?

Many gym-goers genuinely believe that even a short run instantly burns away hard-earned muscle. In sports physiology, this phenomenon is known as the interaction effect or the interference effect.

Scientists have carried out detailed studies of combined strength and running programmes. The results reveal a simple pattern that depends on a person’s level of experience:

• This effect is virtually non-existent in beginners. If a person is just starting to train, aerobic exercise does not prevent the muscles from getting stronger. On the contrary, a well-conditioned heart and a well-developed capillary network accelerate muscle recovery between heavy sets.
• In experienced, highly skilled athletes, daily long-distance runs can indeed slightly slow down the development of maximum explosive strength in the legs. This occurs due to competition between internal cellular signals at the level of sports biochemistry.

For the average person, a moderate amount of aerobic exercise poses no risk to the muscles. Problems only arise when a person exhausts themselves with hours of running whilst severely sleep-deprived and with a severe protein deficiency in their diet.

How to distribute your training loads throughout the week

To maintain vitality and good health, you don’t need to live in the gym.

A healthy weekly routine for the average person can be structured according to the following guidelines:

• Two or three strength training sessions a week, lasting forty or fifty minutes, focusing on basic exercises for the legs, back and chest.
• Two or three aerobic sessions, each lasting thirty or forty minutes at a gentle pace. This could be a brisk walk, a swim in the pool or a leisurely bike ride.
• Regular movement throughout the day. Climbing stairs and walking to work also count towards the WHO’s recommended activity levels.

If you can only fit both workouts into one specific day, the order of the exercises depends on your main goal:

• If your main aim is to strengthen your muscles and build strength, do your strength training first. After that, you can do a light aerobic warm-up for twenty minutes. If you go for a strenuous run before lifting weights, your tired nervous system won’t allow you to lift the weights using the correct technique.
• If your goal is to prepare for a half-marathon, you should do your run first whilst you still have fresh energy.

A safe start for beginners

If you have led a sedentary lifestyle for many years, you must absolutely not start by lifting heavy barbells or doing high-speed runs straight away.

If you are overweight and unfit, the impact of running puts significant strain on your knee and hip joints. For this reason, a safe way to start is by brisk walking on a flat surface or using an elliptical trainer, where your feet remain in contact with the pedals.

Once your ligaments and joints have got used to the movement, you can add simple bodyweight exercises to your routine. Chair squats, high-bar push-ups and kneeling planks allow your body to gradually get stronger without joint pain or the risk of injury.

When exercise requires a mandatory visit to the doctor

Any physical activity is only beneficial if it is completely safe. There are symptoms and conditions under which the intensity of any exercise must be monitored by a doctor.

You must undergo a medical examination before starting any exercise if you have the following symptoms:

• Diagnosed heart disease, a previous heart attack or heart rhythm disorders.
• The onset of a pressing pain or a feeling of tightness in the chest whilst walking briskly or climbing stairs.
• Sudden bouts of dizziness, ringing in the ears or episodes of loss of consciousness.
• Chronic high blood pressure above 140 over 90 millimetres of mercury.
• Severe joint and spinal conditions with persistent pain.

A doctor will help you determine a safe heart rate range and recommend therapeutic exercises that are safe for your body.

Sensible fitness does not require fanaticism or giving up one type of activity in favour of another. Strength training builds a strong physical framework, whilst cardio training maintains vascular elasticity and heart health. Combining the two gives a person high levels of physical performance and many years of active life.

FAQ Answers to frequently asked questions

Which is more effective at lowering blood pressure: cardio or strength training?
Both types of training help to normalise vascular tone. However, moderate aerobic exercise such as walking and swimming produces a faster and more noticeable vasodilatory effect.

Is it possible to lose belly fat solely by doing abdominal exercises?
No. There is no such thing as spot reduction. The body burns fat evenly from all areas when there is an overall calorie deficit, whilst abdominal exercises merely strengthen the muscles beneath the layer of fat.

Does muscle tissue break down during a morning run on an empty stomach?
A short morning run at a gentle pace does not break down muscle tissue, provided you have had sufficient food throughout the day. However, long runs without eating beforehand can force the body to use amino acids as an emergency fuel source.

How many rest days does the body need each week?
For most healthy people, one or two days of complete rest from exercise per week is sufficient for proper recovery of the muscles and nervous system.

Which type of exercise is more important for people over the age of sixty?
In later life, both types of exercise are equally essential. Strength training protects bones from fractures and maintains coordination, whilst aerobic exercise supports the heart and blood supply to the brain.