Quick answer: You can combine cardio and strength training without losing muscle. A large 2022 review found that adding cardio does not reduce muscle growth or maximum strength, although it can slightly blunt explosive power when both are done in the same session. If strength is your priority, lift first, or do your cardio at a different time of day.
Does cardio kill your gains?
For most people, no. A review of 43 studies found that adding cardio to strength training did not reduce muscle growth or gains in maximum strength. Explosive strength, the kind used for jumping and sprinting, may improve a little less, especially when cardio and strength training are done in the same session.
Cardio also brings its own benefits for your heart, lungs and general health, so for most people the best plan includes both.
Should I do cardio before or after weights?
If strength is your main goal, lift first. In a review of studies, doing strength training before cardio gave better gains in lower body strength, with no difference in muscle size or aerobic fitness. If you can, doing them at different times of the day, or on different days, also helps.
What is Zone 2 cardio?
Zone 2 is an easy, steady pace that you could keep up for a long time, such as brisk walking, easy cycling or gentle jogging. A simple check is the talk test for moderate effort: you can talk, but you can’t sing.
It sits within the moderate range, which Mayo Clinic puts at 50 to 70% of your maximum heart rate. Heart rate formulas are only a rough guide, though, because maximum heart rate varies between people. Some medicines, including some for blood pressure, lower your heart rate. If you take them, use the talk test instead and ask your doctor what is right for you. Zone 2 is a good way to build aerobic fitness, but research hasn’t shown that it is the best intensity for everyone, and harder sessions have a place too.
How much cardio and strength training do I need?
The World Health Organization advises adults to do:
- at least 150 to 300 minutes of moderate aerobic activity a week, or 75 to 150 minutes of vigorous activity, or a mix of both
- muscle strengthening activities on 2 or more days a week
Some activity is better than none, so a busy week still counts.
Fitting both into a busy week
- Start with what you can keep up: for example, 2 strength sessions and 2 or 3 cardio sessions of 20 to 30 minutes, and build from there.
- Short sessions count: a brisk walk to work or a 20 minute bike session adds to your weekly total.
- Short on time? Do strength first and finish with a short cardio block, or put cardio on the days you don’t lift.
- Mix it up: walking, cycling, swimming and rowing all count, and variety helps keep training fun.
- Build gradually: increase how long or how hard you train in small steps.
Food and recovery
Carbohydrate refills the glycogen (stored energy) in your muscles, while protein helps them repair. After a hard session, have a meal or snack with both. A useful target from sports nutrition guidelines is about 0.3 g of protein per kg of body weight after key sessions, which is about 20 g for a 65 kg person.
Staying safe
Start slowly if you are new to exercise or coming back after a break, and stop if you feel pain or become unwell. Stop straight away and call 999 if you get chest pain or tightness, pain spreading to your arm, neck or jaw, or you find it very hard to breathe. If you have a health condition, are pregnant, or have recently had a heart attack or an operation, check with your doctor about the right level of exercise for you.
Related reading: strength training for older adults and why you keep getting injured.
Frequently asked questions
Does cardio kill your gains?
For most people, no. A review of 43 studies found that adding cardio did not reduce muscle growth or maximum strength. Explosive power can be slightly blunted.
Should I do cardio before or after weights?
If strength is your main goal, lift first. Strength before cardio gave better lower body strength gains, with no difference in muscle size or aerobic fitness.
How much exercise do I need each week?
The WHO advises at least 150 to 300 minutes of moderate aerobic activity, or 75 to 150 minutes of vigorous activity, plus muscle strengthening on 2 or more days.
What is Zone 2 cardio?
An easy, steady pace where you can talk but not sing. It builds aerobic fitness, but research hasn’t shown it is the best intensity for everyone.
Can I do cardio and weights on the same day?
Yes. If strength is your priority, do weights first. Doing them at least 3 hours apart can help protect explosive power.
Sources
- Schumann et al. 2022, Sports Medicine: concurrent aerobic and strength training
- Eddens et al. 2018, Sports Medicine: the order of strength and endurance exercise
- Storoschuk et al. 2025, Sports Medicine: Zone 2 training review
- Mayo Clinic: Exercise intensity
- World Health Organization: physical activity guidelines 2020
- WHO guidelines on physical activity and sedentary behaviour, 2020
- Bull et al. 2020, BJSM: WHO 2020 physical activity guidelines
- Cleveland Clinic: Glycogen
- ACSM position statement 2016: nutrition and athletic performance
- NHS: How to warm up before exercising
- NHS: Heart attack
Need help with this? Our personal training team at Total Health by Hong Kong Sports Clinic can build a programme around your goals and your week at our Central clinic. Message us on WhatsApp to book.
