Cardio and strength training are both important, but it's easy to end up only doing one of those and conveniently forgetting to get around to the other. I’ve been on both sides of the fence. As a runner, I would go months without lifting a weight or doing any purposeful strength training, because who has the time? And in my more recent life as a lifter, I’d join in the joking about how more than 10 reps is cardio, har har. But here’s the truth: we all need strength training and real cardio.
I think it’s easy to gravitate to one type of exercise because we find it fun or convenient. Then, when we feel like we’re sufficiently challenged, there’s no need to look further, right? I’m already an athlete, I remember thinking during both of my extreme phases. But both times, I was missing something.
What strength training does for you
Most obviously, strength training makes you stronger. That means you’re better able to lift weights, but it also means you build the strength reserves to do better in other sports. Strong legs to help you run up hills, for example. Strength training also means you’ll be stronger in everyday life, and chores like carrying groceries or shoveling snow will feel easier.
Strength training can mean lifting weights, but it can also include other types of resistance training. It’s called “resistance” because you’re literally working against some kind of force. Maybe you’re working with dumbbells or resistance bands, or maybe you’re creating a force to resist with your own body, as in pushups or air squats.
Our muscle mass decreases with age, but the more muscle you have to start with, the better off you’ll be. (There’s no such thing as “too old” to train, and in fact, the older you are the more important it is.) Loss of muscle, called sarcopenia, contributes to the likelihood of falls and fractures. Exercise slows and can possibly reverse that loss. So if longevity is one of your fitness interests, that's all the more reason to prioritize strength training.
Strength training also helps bone health and joint flexibility. People who strength train also tend to have better balance and may have an easier time controlling their weight.
What cardio does for you
Cardiovascular exercise includes steady-state endurance work like jogging, as well as interval training where you alternate between harder and easier work but keep moving the whole time. Ideally, you should do both kinds of cardio, since they each have slightly different benefits. If you're confused about which activities count as cardio, I have an explainer here. Think hiking, running, cycling, or gym machines like the elliptical.
Cardio exercise is great for your heart health, as the name suggests. Regular cardio helps to reduce your blood pressure, reduce your “bad” cholesterol, and increase your “good” cholesterol. It may help you maintain a healthy weight, since burning more calories gives you a little more leeway for extra calories you might want to consume. Both cardio and strength training increase your insulin sensitivity, which is especially important if you have type 2 diabetes or are considered prediabetic.
Besides those benefits, cardio also helps with the other activities you do. With better cardio fitness, you’ll be able to recover more quickly between sets of heavy lifting exercises, and you’ll have an easier time of everyday physical activities like yard work. You’ll also be able to enjoy yourself more if you end up doing physical activities for fun, like going on a hike or walking around a new city when you travel.
How much cardio and strength training is enough?
So now you know that lifting will benefit your ability to cardio activities, and cardio will benefit your lifting. There are also definitely activities that combine both. (If you do Crossfit, for example, or strongman training, you may well have most of your bases covered.) But for simplicity, the physical activity guidelines for Americans break out the two different types.
These guidelines (which agree with those from other major public health organizations) suggest at least 20-30 minutes of strength training, at least twice a week. Most beginner lifting programs will have you work out three times a week, which is great. The minimum is two sessions for each muscle group, so if you prefer to do split your workout into upper-body and lower-body days, make sure you to two of each. If you work your full body in each strength training day, you only need two or three of those workouts per week.
As you get used to strength training, you may want to do more—which is great, as long as you work up to it gradually. While you can do one-off videos or make up a routine out of exercises you like, you’re better off in the long run with a program that gives you a way to progress as you get stronger. There are some great listings of programs at the subreddits r/fitness and r/bodyweightfitness, if you’d like a few to choose from.
For cardiovascular exercise, the recommended minimum is 150 minutes of light exercise like walking, or 75 minutes of vigorous exercise. So if you take a 30-minute walk every weekday at lunchtime, you’ll meet the guidelines. If you use that time to run instead, you’ll exceed the guidelines within three sessions. While the guidelines use minutes of exercise, researchers have calculated that if you prefer step counting, 7,000 to 9,000 steps will get you in the right ballpark.
Again, more is better, so long as you work up to it over time. I started working an evening walk into my routine one summer, and once the weather started to cool down I went for a lunchtime walk and an evening walk. Then, little by little, I replaced some of the evening walks with run/walk sessions, and eventually runs. I felt like my lifting sessions went better than they did before, but I was also happy to know I’m setting myself up for better health in the long term than if I just stuck with one type of exercise.
