How Much Cardio Per Week? What Counts and Where Zone 2 Fits

Search for how much cardio you need and you tend to get two kinds of answers. Health agencies say 150 minutes a week. Training podcasts and wearable apps talk about zones, heart-rate percentages and bigger numbers. It is easy to come away thinking you have to pick a side.

You don't, because the two are answering different questions. This guide starts with the public-health range, shows how to count a real, mixed week against it, and then looks at where Zone 2 fits and what is still uncertain about it.

A note on health advice: This is general information, not medical advice. Most of the research on weekly totals is observational, which means it shows associations rather than proof of cause. If you have a medical condition, are pregnant, or have been inactive for a long time, it is reasonable to talk with a healthcare professional about what suits you.

The 30-second answer

For most adults, the global guideline is at least 150 to 300 minutes of moderate-intensity aerobic activity a week, or at least 75 to 150 minutes of vigorous activity, or an equivalent mix. Count only the minutes that really reach that effort. You do not need Zone 2 or a wearable to do it.

• The range: set by the World Health Organization in 2020 for adults, and echoed by US guidance
• Moderate effort: you can talk but not sing. Vigorous effort: only a few words between breaths
• The counting rule (US convention): moderate minutes + 2 x vigorous minutes
• Strength training: its own recommendation, at least two days a week, and it does not automatically add aerobic minutes
• Zone 2: an endurance-training intensity with no single agreed definition. The guidelines do not require it, and the evidence does not show it is uniquely best for general adults
• Beyond 300 minutes: WHO says you may do more for added benefit, but rates that as a conditional recommendation
• Starting from little: begin small and build up gradually

What the guidelines say

The global reference point is the WHO 2020 guidelines on physical activity and sedentary behaviour, published in the British Journal of Sports Medicine. For adults, WHO recommends at least 150 to 300 minutes of moderate-intensity aerobic activity a week, or at least 75 to 150 minutes of vigorous-intensity activity, or an equivalent combination of the two. It also recommends muscle-strengthening activity at moderate or greater intensity on two or more days a week. The aerobic and muscle-strengthening recommendations are both rated strong. WHO lists these aerobic amounts for adults aged 18 to 64 and applies the same amounts to adults aged 65 and older, who are also advised to add varied multicomponent activity emphasizing functional balance and strength on 3 or more days a week.

Two details in the WHO text matter for everyday counting. First, activity in bouts of any duration counts, so there is no minimum session length. Second, WHO treats going above 300 minutes differently: adults may increase their activity for additional benefit, but that is a conditional recommendation, partly because the evidence cannot say where diminishing returns begin.

The US sources, from the Department of Health and Human Services and the US Centers for Disease Control and Prevention (CDC), say almost the same thing, which is useful corroboration but not independent global guidance. They are US-specific and should be read that way.

Source	Applies to	Moderate-intensity aerobic	Vigorous-intensity aerobic	Mixing the two	Muscle strengthening
WHO 2020	Global, adults	At least 150-300 min per week	At least 75-150 min per week	"Equivalent combination"	2 or more days per week
US Physical Activity Guidelines, 2nd edition (2018)	United States	150-300 min per week	75-150 min per week	Equivalent combination	2 or more days per week
CDC adult guidance	United States	150 min per week	75 min per week	Equivalent mix; 1 vigorous min is about 2 moderate min	At least 2 days per week

The US guidelines are published by the Department of Health and Human Services, and the CDC's adult page is the plain-language version. Notice that the CDC page gives 150 minutes as the figure and says that going beyond it brings even more health benefits, while WHO and the US guidelines express the same idea as a range.

Four kinds of cardio numbers

Part of the confusion is that very different things get called "how much cardio you need." Keeping them apart removes most of the apparent conflict.

A public-health guideline is written for whole populations. It sets a level most people can reach and that is associated with meaningful health benefit. The 150-minute figure is this kind of number. It is expressed in moderate and vigorous effort, because that is something anyone can judge without equipment.

A training prescription is written for a particular goal, such as finishing a marathon or building aerobic base. It uses the language of training: zones, thresholds, weekly hours. Zone 2 belongs here.

A popular claim is a number repeated online with a confident tone. Popularity is not evidence, and these numbers are not guidelines, so this article does not treat them as targets.

An evidence-based conclusion is what the research can actually support, with its limits. Much of it for weekly totals comes from large observational studies, which can show patterns but not prove cause, and a smaller number of trials on specific training formats.

Blur these categories and you get comparisons like "is 150 minutes enough?" that set a training prescription against a public-health minimum, as though both were aimed at the same person with the same goal. They are not.

So "150 minutes versus Zone 2" is not a real contest. One is a minimum-oriented public-health range for general adults, the other is a way of structuring endurance training. They can overlap in a given week. They do not measure the same thing.

Moderate or vigorous?

The guidelines define intensity two ways. In absolute terms it is energy use: moderate activity is roughly 3 to under 6 METs, and vigorous is 6 METs or more (a MET is energy use relative to sitting quietly). In relative terms it is how hard the activity feels to you, which is the version you can use without any gear.

The talk test

The CDC's description is simple. During moderate activity you can talk, but not sing. During vigorous activity you cannot say more than a few words without pausing for breath.

The 0 to 10 effort scale

The same CDC page puts relative effort on a scale from 0 (sitting) to 10 (maximum). Moderate is a 5 or 6, and vigorous begins at 7 or 8. If a walk leaves you at a 6, count it as moderate. If you are at an 8, count it as vigorous.

Pace and steps are rough markers

Speed and step counts can help you calibrate, but they are less reliable than they look. A review of 38 studies by Tudor-Locke and colleagues, a narrative review rather than a trial, treated about 100 steps a minute as a consistent heuristic for moderate-intensity walking in adults, while acknowledging large differences between individuals. A 2025 treadmill study of 48 young adults with obesity in Taiwan found a higher cutoff for moderate walking, around 114 steps a minute. So treat roughly 100 steps a minute as a starting point, not a threshold. Our steps guide goes into daily step counts, which answer a different question from weekly aerobic minutes.

What the cues cannot do

Intensity is relative. The CDC notes that an activity that is vigorous for a person of average fitness may only be moderate for a very fit person. The same pace can also feel harder in heat, on hills or at altitude, so follow how hard it feels rather than speed alone. The talk test also depends on whether you are chatting with a friend or concentrating on the effort. It tracks how hard the effort feels rather than measuring it, so it is best treated as a practical, approximate cue.

Count your minutes

Here is the method in six steps.

1. Pick the activity. Walking, cycling, swimming, sport, anything that raises your breathing.
2. Judge the effort. Use the talk test or the 0 to 10 scale. Be honest: if you could sing, it does not count.
3. Count only qualifying minutes. Time at moderate or vigorous effort. Warm-up, rest breaks, and easy coasting do not count.
4. Convert vigorous minutes. Multiply them by two.
5. Add up the week. Moderate minutes plus doubled vigorous minutes.
6. Compare and qualify. Set the total against 150 to 300, then remember what the number does and does not tell you.

The calculation is:

Weekly moderate-equivalent minutes (US convention) = moderate minutes + (2 × vigorous minutes)

The 2-to-1 conversion is the rule of thumb the CDC states: one minute of vigorous activity is about the same as two minutes of moderate. WHO's own wording is "an equivalent combination," which does not state a ratio, so the exact formula is the US convention.

Moderate minutes	Vigorous minutes	Calculation	Moderate-equivalent minutes
150	0	150 + (2 x 0)	150
0	75	0 + (2 x 75)	150
60	45	60 + (2 x 45)	150
100	25	100 + (2 x 25)	150
0	150	0 + (2 x 150)	300

Every row reaches the same equivalent total from a different mix, which is the point. Which minutes count is the real question, and it comes next.

A worked example. Say you walk for 45 minutes on a Tuesday. The first 5 minutes are an easy warm-up. The next 30 are at a pace where you can talk but not sing. The last 10 are a hard uphill stretch where you can say only a few words at a time. Count 30 moderate minutes and 10 vigorous minutes: 30 + (2 x 10) = 50 moderate-equivalent minutes. The warm-up stays out.

Because bouts of any duration count, three brisk 10-minute walks add the same 30 moderate minutes as one long one. You do not need a wearable for any of this. A note on your phone with minutes and effort is enough, and if you do use a watch, treat its minute counts as a prompt rather than proof.

What counts, what doesn't

Walking. Brisk walking counts. A relaxed stroll does not, and neither does the part of a sightseeing day spent standing, browsing or photographing. If you walk for an hour and spend 25 minutes at a pace where you could talk but not sing, count 25.

Rucking. The backpack does not decide the category. The effort does. A loaded walk that leaves you breathing harder but able to talk is moderate. Our rucking guide covers load and progression, which are separate from how the minutes are counted.

Cycling, swimming and sport. The CDC lists examples: moderate activity includes fast walking, water aerobics, cycling on level ground and doubles tennis, while vigorous activity includes jogging, lap swimming, fast or hilly cycling and singles tennis. The category follows the effort you put in, not the label of the sport.

Intervals. Count the hard efforts as vigorous minutes. Count recovery periods only if you stay at a moderate effort. If you have heard of interval walking, our Japanese walking guide explains what that research did and did not test.

Strength training. The guidelines treat muscle strengthening as its own recommendation, at least two days a week, separate from the aerobic minutes. An ordinary session of sets and rests does not count as aerobic time, even if it is hard. The CDC page on what counts lists strengthening activities as a separate requirement, and our strength training guide covers that side of the week.

A continuous circuit, where you move from exercise to exercise without stopping and stay breathless, is an edge case. The guidelines do not settle how to treat every circuit format, so this guide does not count one by default. If you want to include one, count only the stretches where your effort genuinely reaches moderate or vigorous, and leave out set-up, rest and the time you spent catching your breath.

Four sample weeks

These are illustrations of the method, built from plausible numbers. Illustration, not an individual exercise prescription. None of the totals is a medical clearance or a promise of any outcome, and strength sessions appear only to show that they are not counted as aerobic minutes.

Week	Qualifying activity	Moderate min	Vigorous min	Moderate-equivalent total	Against 150-300
A: Desk-based, brisk walks	5 lunchtime walks of 20 min plus a 40 min weekend walk, all at talk-not-sing effort. Two easy evening strolls not counted	140	0	140 + (2 x 0) = 140	Just under 150
B: Walking plus strength	4 brisk walks of 30 min plus a 30 min level bike ride at moderate effort. Two 40 min strength sessions not counted as aerobic	150	0	150 + (2 x 0) = 150	At the lower end
C: Traveler	4 brisk walks of 40 min, plus 8 hard one-minute stair or hill efforts	160	8	160 + (2 x 8) = 176	Within the range
D: Trek preparation	2 loaded walks of 90 min at moderate effort, a 40 min brisk walk, and a hill session with 20 min vigorous and 10 min moderate	230	20	230 + (2 x 20) = 270	Within the range, below 300

Week A is one illustrative starting point. Most of the effort sits in short walks that clearly pass the talk test, and the evening strolls are left out because they do not. At 140, it is about 10 minutes short of the lower end, which is a sensible thing for the method to reveal rather than a failure.

Week B reaches 150 with moderate effort alone. The two strength sessions meet a different line of the guideline and add nothing to the aerobic total.

Week C shows how little vigorous work changes a total. Eight one-minute efforts add 16 moderate-equivalent minutes. The walking does most of the work, and a traveling routine can lean on walking in just this way.

Week D reaches 270 because the long loaded walks are counted at moderate effort and the hill session contributes vigorous minutes. A trek-training week is still not a template, and it may need more specific preparation than any weekly aerobic total describes.

What more than the minimum adds

Does going past 150 minutes buy anything? Two large observational studies look at all-cause mortality, and they should be read separately. They use different units, comparison groups and methods, and their numbers cannot be stitched into one curve.

	Arem et al., 2015	Garcia et al., 2023
Design	Pooled analysis of 6 US and European cohorts	Dose-response meta-analysis of 94 cohorts
Size	661,137 adults, 116,686 deaths, median follow-up 14.2 years	More than 30 million participants
Exposure	Leisure-time activity, in MET-hours per week	Mostly self-reported non-occupational activity, in marginal MET-hours per week
Comparison	No leisure-time activity	Inactive individuals; each study's least-active category was the referent, and curves start at 0 mMET-h/week
Below the guideline minimum	Hazard ratio 0.80 (95% CI 0.78 to 0.82)	At about half the guideline amount (4.375 mMET-h/week): relative risk 0.77 (0.73 to 0.80)
At the guideline amount	1 to 2 times the 2008 US guideline minimum: hazard ratio 0.69 (0.67 to 0.70)	8.75 mMET-h/week, which the authors equate with 150 min: relative risk 0.69 (0.65 to 0.73)
Higher volumes	3 to 5 times the minimum: hazard ratio 0.61 (0.59 to 0.62). 10 times or more: hazard ratio 0.69 (0.59 to 0.78)	17.5 mMET-h/week: relative risk 0.66 (0.62 to 0.70). Beyond that, differences were small and uncertain
Outcome	All-cause mortality	All-cause mortality

Read the table for the shape, not the decimals. In both studies, the biggest difference appears between doing nothing and doing some activity, with progressively smaller differences at higher volumes. Arem's group concluded that meeting the 2008 US guideline minimum captured most of the longevity association, and that highly active people did not show higher mortality than inactive ones. Garcia and colleagues describe the evidence as weaker at high volumes, where data were sparse.

The limits are real. Garcia's pooled studies relied mostly on self-reported activity, so measurement error is likely there, and the Arem abstract does not describe how activity was measured. Healthier people may exercise more, and people with early illness may exercise less, so cause and effect can blur. Both measured deaths, not injury, fatigue, enjoyment or fitness. None of this shows that more cardio always helps, that 300 minutes is optimal for everyone, or that very high volumes are harmless for any individual.

Where Zone 2 fits

Zone 2 is a concept from endurance training. It is usually described as steady, comfortable effort below the point where breathing and lactate begin to climb sharply. In the 2025 expert commentary by Sitko and colleagues, 14 sport scientists and coaches reached consensus that Zone 2 training should preferably be performed at intensities immediately below the first lactate or ventilatory threshold, using continuous, variable or interval sessions. The same abstract notes that there is no clear consensus among coaches, athletes and scientists on the definition, and that the adaptations expected from Zone 2 are not necessarily unique to it and could come from slightly higher or lower intensities. This is expert opinion, not trial evidence.

Why the label is slippery

A study of 50 cyclists by Meixner and colleagues compared several ways to draw the Zone 2 boundary in the same people: fixed percentages of maximum heart rate, lactate thresholds, ventilatory threshold and others. Fixed boundaries differed widely between individuals, and the authors concluded Zone 2 may not be one universally applicable intensity. It was a laboratory study of cyclists, so it describes how the label behaves, not what any boundary does for health.

That has a practical consequence for wearables. A watch's Zone 2 reading is a device-generated label. It is not a laboratory measurement of your threshold, and a zone drawn as a fixed percentage of maximum heart rate can land in a different place for different people. It can be a handy prompt, but it cannot tell you whether a minute counts toward the guideline, and you do not need one to count.

What the evidence supports

The most direct appraisal is a 2025 narrative review in Sports Medicine by Storoschuk and colleagues, titled "Much Ado About Zone 2." In the abstract, the authors note that the popular Zone 2 advice leans on observational data from elite endurance athletes. They argue this conflicts with evidence favoring high-intensity exercise for mitochondrial and cardiometabolic health, and conclude that current evidence does not identify Zone 2 as optimal for mitochondrial or fatty-acid oxidative capacity. They add that higher intensities matter for cardiometabolic benefit, especially when training volume is low. It is a narrative review, so it reflects the authors' reading of the literature rather than a pooled analysis.

Put together: Zone 2 is a legitimate way to build endurance, many endurance athletes use it, and it may overlap with moderate-intensity effort for some people, depending on fitness, though the two categories do not map one-to-one. It is not required to meet the guideline, and the evidence does not show it is uniquely best for general adults.

Question	Public-health guidance (WHO, CDC)	Zone 2 training advice
Written for	General adult population	People structuring endurance training
How intensity is described	Moderate or vigorous, by METs or effort	Varies; one expert panel favors immediately below the first lactate or ventilatory threshold; some devices show heart-rate zones
How you can check it	Talk test, 0 to 10 effort scale	Laboratory tests, or device-estimated heart-rate labels
Weekly target	150-300 min moderate, 75-150 min vigorous	Varies by coach; no guideline figure
Strength of backing	Guideline development process; strong recommendation	Expert commentary and a narrative review; not shown to be optimal for general adults

Bursts and intervals

Shorter and harder formats get a lot of attention, and three kinds of evidence get mixed together. They are worth separating.

Exercise snacks are short, structured bouts. A meta-analysis by Rodríguez and colleagues, published online in 2025 and included in the January 2026 issue of the British Journal of Sports Medicine, pooled 11 randomized trials with 414 participants. Going by its abstract, cardiorespiratory fitness improved in adults, with moderate certainty, while effects on leg strength and cardiometabolic markers were not significant. The trials were short and mostly involved women.

Vigorous lifestyle bursts are a different thing: brief, unplanned effort in daily life, like hurrying up stairs. A Nature Medicine cohort study of 25,241 UK adults who did not exercise linked around three such bouts a day with lower mortality, but it was observational and its authors cannot rule out reverse causation. It shows an association, not that bursts cause longer life.

High-intensity interval training (HIIT) alternates hard and easy work. A 2026 Cochrane review of healthy sedentary adults aged 18 to 64 found it may raise VO2max (a measure of aerobic fitness) slightly more than moderate continuous training (a difference of about 1.4 mL/kg/min), with low certainty, and every included trial was supervised. It does not tell us about other populations, unsupervised settings or other interval formats.

None of this overturns the weekly guideline. These are formats for accumulating minutes, each backed by a different strength of evidence.

Who should adjust

The general guidance is for adults, but it is not one-size-fits-all. WHO's text says risks can be managed by starting with small amounts and gradually increasing frequency, intensity and duration. For adults living with chronic conditions, it advises aiming for activity according to their abilities, and it says they may consult a physical activity specialist or a healthcare professional about the right types and amounts. WHO also recommends at least 150 minutes of moderate activity for pregnant and postpartum women without contraindications, with advice to avoid excessive heat.

If you are starting from very little, the counting method is more useful as a way of seeing progress than of chasing a target. Moving from 40 minutes a week to 70 is a real change. Avoid jumping straight to vigorous effort. A structured plan such as our 30-day home workout can give you a ramp, though it is not a prescription for you in particular.

If you get new chest pain, dizziness or unusual breathlessness during activity, stop exercising and seek medical advice promptly. Seek emergency care if symptoms are severe, persist or do not ease with rest. An activity total is not a measure of whether exercise is safe for you.

The bottom line

The weekly aerobic guideline for adults is at least 150 to 300 minutes of moderate activity, or 75 to 150 minutes of vigorous activity, or an equivalent mix. Count the minutes that truly reach that effort, double the vigorous ones using the US convention, add up the week, and compare. Strength training is its own line, and Zone 2 is a way of training, not a requirement.

The honest limits are worth keeping in mind. Most of the weekly-total evidence is observational, the Zone 2 evidence for general adults is thin, and the cues for intensity are practical rules of thumb. If this week fell short of 150, that is information, not a verdict. Add a little, keep it comfortable, and build from there.

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• How Many Steps a Day Do You Actually Need? (Not 10,000)
• Japanese Walking: What It Is and What the Science Shows
• How Much Strength Training Do You Actually Need?
• Rucking for Beginners: How Much Weight and What It Burns
• How to Stay Fit While Traveling: 15 No-Gym Workouts