Aerobic activity (“cardio”) is any activity that keeps large muscles moving rhythmically for a sustained period and raises your heart rate and breathing: brisk walking, cycling, swimming, dancing, running. It is one of the two pillars of the U.S. Physical Activity Guidelines for Americans. This guide explains how much aerobic activity the guidelines recommend, how to judge intensity without equipment, how to choose between walking, running, cycling and low-impact options, and how to build up safely. It is general fitness information for healthy adults, not medical advice.
How much aerobic activity?
For substantial health benefits, the guidelines recommend 150 to 300 minutes a week of moderate-intensity aerobic activity, or 75 to 150 minutes of vigorous activity, or an equivalent combination, preferably spread throughout the week. More than 300 minutes of moderate activity brings additional benefits. For people starting out, the guidelines’ principle is to “start low and go slow”, and some activity is better than none.
Judging intensity: the talk test
| Intensity | Talk test (HHS guidelines) | Typical examples for many adults |
|---|---|---|
| Light | Easy conversation and singing | Easy walking |
| Moderate | Can talk, but not sing | Brisk walking, easy cycling, water aerobics |
| Vigorous | Cannot say more than a few words without pausing for breath | Running, fast cycling, swimming laps |
The guidelines note intensity is relative: an activity that is moderate for one person may be light for a fitter person, who may need more vigorous activity for some benefits.
Choosing your cardio
Walking
Walking needs no equipment, suits almost every fitness level and is easy to fit into daily life. Brisk walking is moderate intensity for most beginners. Comfortable, supportive shoes and safe routes are all you need. See walking workouts.
Running
Running is vigorous for most people and time-efficient, but it is higher impact. Beginners usually start with walk-run intervals and increase running time gradually. See running workouts.
Cycling
Cycling, outdoors or on a stationary bike, is lower impact on the joints and easy to adjust in intensity. Outdoors, wear a helmet and follow road safety rules. See cycling workouts.
Low-impact options
Swimming, water aerobics, elliptical trainers, rowing and dancing can raise the heart rate with less impact. They suit people with joint discomfort or those returning after a break. See low-impact cardio.
Building up gradually
The NHLBI suggests starting with just 5 to 10 minutes a day if you have not been active, and building up gradually. A simple progression:
| Weeks | Plan (example: walking) |
|---|---|
| 1–2 | 10–15 minutes, 3–5 days a week, at an easy-to-brisk pace |
| 3–4 | 20 minutes, 5 days a week |
| 5–6 | 25–30 minutes, 5 days a week (about 150 minutes) |
| 7+ | Add hills, intervals or a longer weekend session as you feel ready |
Increase only one thing at a time (duration, frequency or intensity), and keep easy days between harder ones.
Warm-up and cool-down
The NHLBI recommends a warm-up of about 5 minutes at a slow to medium pace (up to 10 minutes for strenuous activities such as jogging) and a cool-down of about 5 minutes, slowing gradually, for example moving from jogging to walking, because stopping abruptly can cause dizziness. The guidelines note warm-up and cool-down time can count towards aerobic minutes.
Exercising safely outdoors
- Dress for the weather and drink water in heat.
- Choose well-lit, safe routes; be visible to traffic.
- Adjust intensity in heat, cold or high pollution.
- The guidelines encourage sensible choices about when, where and how to be active and using appropriate gear.
Combining cardio with strength
The guidelines recommend muscle-strengthening activities on 2 or more days a week in addition to aerobic activity. See strength training basics and a full weekly plan in beginner workout plan.
A beginner walk-run plan
If you want to progress from walking to running, a gradual walk-run approach follows the guidelines’ “start low and go slow” principle. Do three sessions a week with rest days between, after a 5-minute brisk walking warm-up:
| Weeks | Intervals (repeat for 20–25 minutes) |
|---|---|
| 1–2 | Run 1 minute, walk 2 minutes |
| 3–4 | Run 2 minutes, walk 2 minutes |
| 5–6 | Run 3 minutes, walk 1–2 minutes |
| 7–8 | Run 5 minutes, walk 1 minute |
| 9+ | Gradually lengthen continuous running |
Repeat a week whenever it feels too hard; there is no deadline. Run at a pace where you can still speak in short sentences, and finish with a 5-minute walking cool-down.
Using heart rate and devices
Fitness trackers and heart-rate monitors can help you see trends, but the talk test from the guidelines works well without any device. If you use a monitor, compare readings over weeks rather than chasing a particular number in each session, and remember that medications and health conditions can affect heart rate; ask your doctor about targets if you have a heart condition.
Staying motivated
Variety helps: alternate walking routes, try a bike ride at the weekend or join a group class. Many people find a walking partner or club keeps them consistent. Set a weekly minutes goal rather than a daily one, so a missed day does not feel like failure.
Frequently asked questions
Does walking count as exercise?
Yes. Brisk walking is moderate-intensity aerobic activity for most adults and counts towards the guidelines.
Is it better to do cardio every day?
Spreading activity through the week is preferable, according to the guidelines. Mix harder and easier days, and include rest when you need it.
All cardio guides are under Cardio and Conditioning.
What if I miss a week?
Restart a little below where you left off and build back up gradually.
