How NiaHealth Builds Your Exercise Plan

Your exercise plan is built around three tiers: Building momentum, Active and High performer. We place you in one based on the weekly cardio you tell us about, and each tier has its own focus areas and targets. Those targets come from the research linking physical activity and fitness to longevity. Daily steps and breaking up sitting are part of every tier. Effort is described first by how hard it feels and whether you can still talk, with heart-rate zones as an estimate.

If you have been a member for a while, this is a change. Earlier versions of your plan gave every member the same four weekly goals: 180 minutes of Zone 2 cardio, 60 minutes of high-intensity (Zone 5) work, 120 minutes of strength training and 30 minutes of stability training. If you were a long way from those goals, your plan broke the gap into smaller steps, but the end goals were the same whether you were just getting started or already training most days. The new framework replaces one set of goals for everyone with targets that depend on where you are starting.

This article explains the ideas behind the new plan, how each tier works, where zones still fit in, and where the evidence is still limited.

The ideas behind the new plan

1. Targets come from the evidence on longevity

The new plan leads with the kinds of activity that have the clearest links to lower mortality and better fitness.

Moderate-to-vigorous activity is consistently associated with lower mortality. Large cohort studies from UK Biobank, NHANES and national health surveys consistently show that 150 to 300 minutes a week of moderate-to-vigorous activity, measured by self-report or accelerometer, is associated with substantially lower all-cause mortality. The steepest reduction in risk comes from moving from no activity to some.

Vigorous minutes may be worth more than guidelines assume. A UK Biobank analysis of 73,485 people, with activity measured by accelerometer, found that for all-cause mortality, 1 minute of vigorous activity was equivalent to about 4 minutes of moderate activity.¹ That is substantially higher than the 2-to-1 ratio assumed in current guidelines. This is recent evidence, so we use it to explain the value of harder effort. We do not use it to convert your minutes: in your plan, a minute is a minute.

Short bursts of vigorous everyday activity matter if you are not exercising yet. A UK Biobank study of about 25,000 people who did no structured exercise² found that a median of 4.4 minutes a day of brief vigorous bursts during daily life, such as stair climbing, carrying things or walking fast, was associated with 26–30% lower all-cause mortality and 32–34% lower cardiovascular mortality. This is the strongest evidence we have for people who are not yet doing structured exercise. The effect diminishes once people are exercising regularly.

Most of the benefit of activity may work through fitness. Cardiorespiratory fitness, measured as VO2 max, is a stronger predictor of mortality than self-reported physical activity.^3,4 When fitness is added to statistical models that include physical activity, the mortality benefit of activity is substantially reduced, which suggests that most of that benefit works through improving fitness.

High-intensity intervals are the most effective way to improve VO2 max. Interval training above the second metabolic threshold is the most effective intervention we know of for improving VO2 max.⁵ An umbrella review of 24 systematic reviews found improvements of 3.25 to 5.5 mL/kg/min compared with no exercise.⁶ In a 6-week randomized trial of 84 healthy young adults, training only below the first threshold did not significantly improve VO2 max, while training above the first threshold, and especially above the second, produced clinically meaningful improvements.⁷ That is a single trial in healthy young adults, so we treat that particular finding as low to moderate evidence. Some studies have shown VO2 max improvements from training below the first threshold, although the effect is not as large as with high-intensity intervals. For people who are just getting started, we still expect VO2 max to improve with lower-intensity training.

2. Your starting point decides what your plan focuses on

Because the evidence differs depending on how active you already are, your plan does too. If you are doing less than 150 minutes of cardio a week, your plan builds on the evidence for everyday vigorous bursts, steps, strength and breaking up sitting. If you are doing 150 to 299 minutes, it focuses on moderate-to-vigorous cardio and strength. If you are doing 300 or more, it focuses on VO2 max, measured in a lab, and the interval and cardio training that improve it.

3. Effort is described by how it feels first

Your plan describes intensity in this order:

• RPE (rate of perceived effort). How hard the activity feels, out of 10. A 5 or 6 is moderate. A 7 or 8 is vigorous.
• The talk test. At moderate intensity you can talk but not sing. At vigorous intensity you can only say a few words at a time. The talk test has been validated against the first metabolic threshold in multiple populations.^8,9
• Heart-rate zones, as an estimate only.

This order follows a 2025 joint position statement from the American College of Sports Medicine and Exercise & Sports Science Australia (ACSM/ESSA).¹⁰ It recommends RPE and the talk test as the most practical intensity guides when lab-based thresholds are not available, and recommends against prescribing intensity by percentage of maximum heart rate, heart rate reserve or VO2 max, because these do not produce the same metabolic response across people with different fitness levels.

There are three reasons heart rate makes a less reliable guide on its own:

• Fixed percentages do not fit everyone. Studies show that at 80% of maximum heart rate, about half of people are above their first metabolic threshold and half are below it. Common wearable zone systems put the line between Zone 3 and Zone 4 at 80%. So at a heart rate those systems would place at the top of Zone 3, many people may still be in Zone 2, if Zone 2 is defined as below the first threshold.
• Heart rate lags behind effort. The research supports a lag of 30 seconds to 2 minutes, and the lag appears to be longer in less fit people and on the first interval of a session than on later ones. That makes wearable zone time unreliable for short, high-intensity intervals. Do not treat your heart rate early in an interval as a measure of how hard you are working.
• Wearables tend to under-count moderate-to-vigorous activity. One study of Apple Watch found it underestimated these minutes by about 46% on average.¹¹ That comes from a single study of a single device, and the error varies considerably with the type of wearable, the activity and the fitness of the person. A low number on your watch is not evidence that you did not do the work.

Strength training uses a different measure: RIR (reps in reserve), the number of good-form repetitions you could still complete at the end of a set. About 6 reps left is moderate. About 3 left is vigorous. Lower is harder.

Where heart-rate zones fit in

You will still see zones in your plan. You report your weekly minutes by zone in your checkup, the Active cardio target is set at Zone 3 and above, High performer intervals are in Zone 4–5, and your wearable can show your time in each zone. What has changed is how much weight zones carry and what each zone is understood to mean.

Zones are a secondary tool. The mortality research classifies intensity by energy cost (METs) or by accelerometer. The VO2 max research more often uses metabolic thresholds. There is minimal research on zone-based training, and no study that directly links Zone 2 training to mortality, VO2 max improvements or performance. So we lead with targets grounded in the mortality evidence and use zones as a guide alongside RPE and the talk test.

Moderate intensity starts at Zone 3. The physical activity guidelines most people know, such as 150 to 300 minutes a week of moderate-to-vigorous activity, are not anchored to heart-rate zones or to metabolic or ventilatory thresholds, so there is uncertainty about exactly where moderate and vigorous activity fall on the spectrum of zones. The ACSM/ESSA statement recommends standardizing the terminology so that moderate intensity sits between the first and second metabolic thresholds (often written MT1 or VT1, and MT2 or VT2). In the five-zone model, that corresponds to Zone 3 and above. By that classification, Zone 2, which sits below the first threshold, is low intensity.¹²

We want to be precise about how strong this is. It is expert consensus, the most harmonized classification available, and we rate it as moderate evidence at best. Strictly speaking, we do not know whether Zone 2 minutes should count toward moderate-intensity guidelines, because zones and physical activity guidelines have never been standardized against each other, and there is little research supporting the zone system itself. What we no longer do is describe Zone 2 as moderate intensity. Your earlier plan described it as working at around 70% of your maximum heart rate.

What this means for Zone 2

Zone 2 is still part of your plan. It counts toward your tier placement, it is the easy part of the High performer cardio split, and it counts toward the steady cardio targets described below. It is no longer a headline target on its own.

That reflects the evidence, not a finding that Zone 2 is bad for you. Zone 2 targets like the one in our earlier plan appear to derive from a popular interpretation of work by San-Millán and Brooks.¹³ Their research proposed that the exercise intensity at which blood lactate first begins to rise above baseline is the intensity that optimizes fat burning in the mitochondria. But their published work does not refer to training zones, and the idea has not been tested against mortality outcomes. A 2025 narrative review¹⁴ concluded that there is a lack of evidence that Zone 2 training improves mitochondrial function or lowers mortality. The problem is limited evidence, not evidence that Zone 2 has no benefit.

The three tiers

The tier decides your focus areas and targets, and everyone in a tier gets the same target numbers. A tier is a starting point, not a ranking.

How we place you

In your checkup questionnaire you tell us how many minutes a week you spend at different effort levels. We add up your Zone 2, Zone 3 and Zone 4–5 minutes, and that total decides your tier.

• Zone 0–1 minutes do not count, and neither do strength or stability minutes, steps, sitting or wearable minutes.
• Minutes are counted as they are. One vigorous minute is not multiplied up for placement.
• A question you leave blank is skipped, not read as zero. If you did not answer any of the cardio questions, you start in Building momentum and we do not state a weekly total for you.
• Wearables never move your tier. Your wearable can show how you are tracking against your targets, but it does not decide which tier you are in.

You may notice that Zone 2 counts toward placement but, on the Active tier, does not count toward the cardio target. That is on purpose. Members often do not log enough Zone 3 for the cutoffs to sort people usefully on Zone 3 and above alone, so easy cardio still helps place you. Once you are in Active, the plan asks for minutes at moderate intensity or above.

How your tier changes

Your tier changes in only two ways: when you complete a new checkup and your updated exercise answers place you in a different tier, or when your care team changes it. There is no waiting period and no automatic movement between tiers, and connecting a wearable or logging more activity does not change it.

Your care team can change your tier if the placement is not right for you. For example, a member who does 300 minutes a week of Zone 2 and no moderate work still places as a High performer, and that plan asks for intervals and a lab VO2 max test. Injury or illness does not automatically move you down a tier. If your plan is no longer safe, your care team can change your tier or your recommendations. If they change your tier, your next checkup answers take over from that change.

Building momentum

This tier is for members reporting under 150 minutes of cardio a week. It has four focus areas, and all four are primary. Zone language is not the lead here, and we do not push a VO2 max test, because the recommendations on this tier do not depend on one.

High-intensity bursts: 5 a day. A high-intensity burst is a brief everyday effort, about 1 to 2 minutes, that quickly raises your heart rate and leaves you breathing hard: taking a flight of stairs at a purposeful pace, carrying groceries or something moderately heavy, walking briskly or choosing an incline. This focus area is built on the Stamatakis research above.²

Daily steps: 7,500 a day. Steps have a dose-response relationship with mortality, and a Lancet meta-analysis of 57 studies found the benefit begins at around 3,000 to 4,000 steps a day.¹⁵ Use the target as a direction, not a pass-or-fail score: start from your current average and add walking where it fits.

Strength training: 60 minutes a week. Muscle-strengthening activity has a mortality benefit that is separate from the benefit of cardio. Sixty minutes a week is a concrete, achievable target at this tier. Break the total into sessions that fit your week; consistency matters more than a perfect format. Aim to stop each set with about 6 reps in reserve.

Sitting and breaks. Your Sedentary Index combines how much time you spend sitting each day with how often you take a break; a lower number is better. Prolonged sitting carries health risk regardless of how much you exercise, and 10 to 12 hours a day raises it further. The goal is to break up uninterrupted daily sitting throughout the day, with at least one short break an hour: standing during calls, a walking meeting, a stretch, or getting up for water or a lap of the room.

Active

This tier is for members reporting 150 to 299 minutes of cardio a week.

Active cardio: at least 150 minutes a week at Zone 3 or above. This means moderate intensity or above: an RPE of 5 to 6 out of 10, or a pace where you can talk but not sing. Zone 2 is below moderate and does not count toward this 150. Minutes are counted as they are, and there is no separate vigorous-minutes target. For context, the evidence suggests 1 minute of vigorous effort is worth about 4 minutes of moderate effort for mortality benefit.¹

Earlier versions of the plan told members to minimize Zone 3. On this tier, Zone 3 counts toward your cardio target, and it can be a useful route to more moderate-to-vigorous minutes, especially if something makes vigorous work hard for you to fit in.

Strength training: 2 or more sessions a week. Work between moderate effort (about 6 reps in reserve) and vigorous effort (about 3 reps in reserve).

Supporting: daily steps and sitting. These stay on your plan, with the same 7,500-step target and the same goal of breaking up uninterrupted daily sitting. They are supporting rather than primary not because they matter less to your health, but because someone already training at this volume has larger gains available in cardio and strength. The harmful effects of sitting appear to be reduced in more active people, but hitting your cardio target does not cancel them out.

VO2 max. On this tier we may suggest a lab VO2 max test for a more individualized fitness baseline.

High performer

This tier is for members reporting 300 or more minutes of cardio a week.

VO2 max. This is the central fitness measure on this tier, and we only use a lab result. If you do not have one on file, booking a test is the first step in your plan, with a retest in about 6 months. Cardio is the primary driver of VO2 max; strength training supports it but plays a secondary role.

Intervals: about 60 minutes a week in Zone 4–5. These are vigorous efforts, an RPE of 7 to 8 out of 10. A meta-analysis of 53 randomized trials informs the interval shape:¹⁶ efforts of 3 to 4 minutes at around 95% of maximum heart rate, about 4 minutes easy between them, at least 15 minutes of hard work per session, 3 to 5 sessions a week. Remember heart-rate lag: go by effort rather than waiting for your watch to catch up, especially on the first interval.

Cardio volume: about 300 minutes a week, roughly 240 easy and 60 hard. The easy minutes are Zone 2, or below your first threshold. The 60 hard minutes are the interval target above, not an extra 60 on top. This roughly 80/20 split is consistent with the polarized training evidence, which has found that distribution more effective for improving VO2 max than threshold training in trained athletes.^17,18 That evidence is moderate to strong, and the effect is limited to trained athletes.

About Zone 3 on this tier. Zone 3 is not bad. For most training goals, time there carries a higher recovery cost relative to its benefit, because it costs more recovery than Zone 2 without maximally stimulating VO2 max. Unless you are training for an endurance event, keep easy sessions easy and hard sessions hard to protect the quality of your recovery. Threshold training in Zone 3 is supported by evidence for specific endurance goals, such as preparing for a marathon.¹⁹

Strength training: 2 or more sessions a week at vigorous effort. Across most sets, finish with about 3 reps in reserve while keeping good form.

Supporting: daily steps and sitting. The same 7,500-step target and the same goal of breaking up uninterrupted daily sitting.

Why we only use a lab VO2 max

We do not use wearable VO2 max estimates in your plan. An umbrella review of 653 studies found that wearables overestimate VO2 max by about 9.8% on average during exercise tests and about 15.2% at rest.²⁰ The error depends on the wearable and the person, but error ranges of that size are too large for clinical decisions. A lab test (a cardiopulmonary exercise test, or CPET) is the only way to actually measure VO2 max.

Why stability is not a target

Stability is not a focus area on any tier, and stability minutes do not count toward strength. Balance and core stability training have evidence for preventing falls and injuries, but not the same direct evidence on mortality as cardio or strength training. We also decided not to count stability work toward your strength target. The evidence on mortality and other relevant disease outcomes is not as strong for stability as it is for resistance training, and if stability work counted toward a strength target, you might believe you were getting the benefits of strength training when you were not. The trade-off is that some strength benefits from stability work, such as bodyweight exercises in pilates or yoga, are not credited. We think keeping them separate is still the most evidence-based approach.

When high-intensity exercise isn't right for you

If you have reported an injury or chronic pain, your plan will not prescribe intervals or high-intensity work. Your recommendation will name a lower-impact route to your tier's cardio target instead, and keep strength work within a pain-free range.

Your clinician can also limit your cardio to Zone 3 and below. When that happens, your plan switches to a steady cardio version: continuous movement that deepens your breathing while you can still talk.

In this version, Zone 2 counts toward your cardio target and the VO2 max measure is removed from the plan. Your strength, steps and sitting focus areas do not change.

What this means for you

If you are on Building momentum, your plan focuses on short bursts of hard everyday effort, daily steps, strength training and breaking up sitting.

If you are on Active, focus on building your cardio minutes at moderate intensity and above, and on regular strength sessions. Use RPE or the talk test to check your effort.

If you are on High performer, book a lab VO2 max test if you do not have one, keep your easy sessions easy and your hard sessions hard, and keep up your strength training.

If your wearable and your plan disagree, remember that wearables can under-count moderate-to-vigorous minutes and that heart rate lags during short intervals. For short hard efforts, go by RPE or the talk test.

Takeaways

• Your plan places you in one of three tiers based on the weekly cardio you report, and each tier has its own focus areas and targets. Wearables never move your tier.
• The targets lead with the evidence on longevity: moderate-to-vigorous activity, short vigorous bursts if you are not exercising yet, and VO2 max, which high-intensity intervals improve most.
• Building momentum focuses on high-intensity bursts, steps, strength and breaking up sitting. Active focuses on 150 minutes at Zone 3 or above and 2 or more strength sessions. High performer focuses on VO2 max, about 60 minutes of intervals within roughly 300 minutes of cardio, and strength.
• Effort is described first by RPE, then by the talk test, and then by heart-rate zones as an estimate. Strength uses reps in reserve.
• Zones are still in your plan as a secondary tool. Moderate intensity starts at Zone 3, and Zone 2 is low intensity under the 2025 ACSM/ESSA classification. Zone 2 still counts toward your tier and is the easy part of High performer training.
• We only use lab-measured VO2 max. Stability is not a target and does not count toward strength.
• If high-intensity work is not right for you, your plan switches to steady cardio.

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This article is for general education and isn't a substitute for personalized medical advice. Talk to a qualified health professional before starting a new exercise program, especially if you have an existing health condition.