Do You Need Cardio If You Already Strength Train?

Strength training has become much more popular over the last decade, and rightly so. Building and maintaining muscle, improving bone density, increasing strength and preserving physical function are all hugely important for long-term health. But as strength training has grown in popularity, so has the idea that cardio is somehow optional if you already lift weights.

The reality is that strength training and cardiovascular training do different jobs. There is some overlap between the two, but one does not completely replace the other. A hard resistance-training session can raise your heart rate significantly, especially when exercises are performed in circuits or with shorter rest periods, but that does not necessarily produce the same adaptations as dedicated aerobic work.

Strength Training and Cardio Do Different Jobs

Strength training primarily improves muscular strength, muscle mass, bone health and your ability to produce force. Cardiovascular training places a greater demand on the heart, lungs and circulatory system, improving the body’s ability to transport and use oxygen efficiently.

This distinction is reflected in current World Health Organization guidelines, which recommend that adults complete at least 150–300 minutes of moderate-intensity aerobic activity per week, or 75–150 minutes of vigorous activity, alongside muscle-strengthening activity on at least two days per week. In other words, the recommendation is not strength or cardio. Ideally, it is both. (who.int)

That does not mean everyone needs to spend hours running or cycling every week. It simply means there are benefits to developing both muscular strength and cardiovascular fitness, rather than assuming one automatically covers the other.

Why Cardiovascular Fitness Matters

One of the most important reasons to include some form of cardiovascular training is the relationship between cardiorespiratory fitness and long-term health. Cardiorespiratory fitness describes how effectively the heart, lungs and muscles work together during sustained activity, and the evidence linking it with health outcomes is particularly strong.

A major 2024 review published in the British Journal of Sports Medicine analysed data from 26 systematic reviews covering more than 20.9 million observations. Higher cardiorespiratory fitness was consistently associated with a lower risk of premature death and a range of chronic diseases, while every one-MET increase in fitness was associated with an approximately 11–17% lower risk of all-cause mortality. (pubmed.ncbi.nlm.nih.gov)

That does not mean everyone needs the cardiovascular fitness of an endurance athlete. It simply highlights that having a heart, lungs and circulatory system capable of handling physical demand is an important part of overall health.

But Doesn’t Strength Training Improve Your Heart Too?

It does. Strength training can contribute positively to cardiovascular health, improve blood pressure, enhance insulin sensitivity and reduce several cardiovascular risk factors. The key point is that the adaptations are not identical.

Aerobic training is particularly effective at improving the ability to sustain work and increase measures such as VO₂ max, while resistance training is particularly effective at increasing strength and muscle mass. Combining the two allows you to develop a broader range of physical qualities rather than relying heavily on one form of training.

Research looking at combined training supports this approach. A 2024 systematic review examining people with coronary artery disease found that combining aerobic and resistance exercise produced greater improvements in cardiorespiratory fitness than aerobic training alone, while also improving lean body mass and body-fat percentage. Other research has shown that combining aerobic and resistance training can significantly reduce both systolic and diastolic blood pressure in adults with hypertension. (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov)

The broader message is simple: strength and cardiovascular training complement each other rather than compete with each other.

Cardio Doesn’t Have to Mean Running

One of the biggest misconceptions around cardio is that it has to mean long-distance running or spending hours on a bike. It does not. Cardiovascular training simply means placing enough demand on your aerobic system for long enough to create an adaptation.

Depending on the individual, that could come from brisk walking, cycling, rowing, swimming, running, hiking, conditioning sessions or sport. For someone who already plays football, padel, tennis or another active sport several times per week, they may already be getting a significant cardiovascular stimulus without needing to add much structured cardio.

On the other hand, someone who strength trains two or three times per week but spends most of the rest of the week sitting down may benefit much more from deliberately adding regular aerobic work. This is where context matters. The amount of extra cardio someone needs depends on what the rest of their week already looks like.

What About High-Intensity Intervals?

Intervals can be a very useful way of improving cardiovascular fitness, particularly for people who do not enjoy long periods of steady-state cardio. Shorter, harder periods of work on a bike, rower or running track, separated by recovery periods, can provide a strong cardiovascular stimulus in a relatively short amount of time.

That said, harder is not always better. Lower and moderate-intensity exercise still has significant value because it allows people to accumulate more activity with relatively little fatigue and can be easier to recover from alongside strength training.

For most people, a mixture works well. Some harder work can help improve fitness quickly, while easier aerobic work can improve endurance and provide additional weekly activity without placing excessive stress on the body.

Will Cardio Affect Your Strength Gains?

Another common concern is that cardio will interfere with strength or muscle gains. In very high volumes, particularly when someone is combining large amounts of endurance training with a demanding strength programme, recovery and total training load certainly become important.

For the average recreational exerciser, however, sensible amounts of cardiovascular work are unlikely to meaningfully interfere with progress in the gym. The bigger issue is usually poor recovery, inadequate nutrition or simply trying to do too much at once.

Two or three structured strength sessions alongside regular walking, sport or one or two cardiovascular sessions is very different from completing heavy strength training while also doing several hours of endurance work every day. As always, the training needs to match the individual and their goals.

How Much Cardio Do You Actually Need?

There is no perfect number that applies to everyone. Someone who plays football twice per week will have very different requirements from someone whose only exercise is two gym sessions. Age, fitness, injury history, recovery, lifestyle and personal goals all need to be considered.

As a general reference point, the World Health Organization recommends 150–300 minutes of moderate aerobic activity or 75–150 minutes of vigorous activity per week. That total can come from structured exercise, sport and general physical activity rather than needing to come entirely from dedicated cardio sessions. (who.int)

For many people, something as simple as strength training two or three times per week, walking regularly and completing one or two sessions that genuinely challenge the cardiovascular system can create a very well-rounded training week.

Strength and Fitness Should Work Together

At SPC, we do not see strength and cardio as opposing forms of training. Being strong is important, but so is being able to move, recover, work hard and maintain a healthy cardiovascular system.

You do not need to choose between being strong and being fit. Strength training helps keep you strong, muscular and physically capable, while cardiovascular training helps develop the heart, lungs and aerobic system that support everything else you want to do.

For most people, the goal should be broader than simply lifting more weight or running further. The aim is to stay strong, maintain good aerobic fitness, move well and remain physically capable for as long as possible.

That is why the best long-term approach usually includes both.

References

World Health Organization. WHO Guidelines on Physical Activity and Sedentary Behaviour. WHO, 2020. (who.int)

Lang JJ, Prince SA, Merucci K, et al. Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies. British Journal of Sports Medicine. 2024;58:556–566. (pubmed.ncbi.nlm.nih.gov)

Abushamat LA, et al. Effects of muscle strength training combined with aerobic training versus aerobic training alone on cardiovascular disease risk indicators in patients with coronary artery disease: a systematic review and meta-analysis of randomised clinical trials. 2024. (pubmed.ncbi.nlm.nih.gov)

Corso LML, et al. Exercise characteristics and blood pressure reduction after combined aerobic and resistance training: a systematic review with meta-analysis and meta-regression. 2023. (pubmed.ncbi.nlm.nih.gov)