Hume watches three things at once: how well you recover, how resilient your heart is and your metabolic signals. If they drift from your usual range in an odd way, the app flags it and tells you your body may be carrying more strain than normal.

Think of it as a nudge to look at your week: sleep, training load, late nights. None of this is a diagnosis, and it won't stand in for your doctor. HLTH gives you a daily detail screen where you can scroll back through your readings and spot shifts yourself.

What it means for you: a band that compares you with your own normal every day gives you an earlier nudge to rest or change a habit.

The question behind this band is simple: am I ageing well? Put two people born in the same year side by side and one may be ageing far faster than the other, with nothing on their passports to show it.

Metabolic Momentum is Hume's running measure of how fast you're ageing, so you can see whether this month's habits are buying you time or costing you it.

The app shows your Biological Age next to your real age, so the gap between the two is right there on screen.

Check your ageing pace each week. If it has crept up, you'll see it, and you can watch whether more sleep or more movement brings it back down.

HLTH scores your sleep, gives you an Energy Score and tracks stress and heart rate each day. Look through its feature list and you won't find a biological age or pace-of-ageing figure.

What it means for you: a Biological Age figure gives months of habits one number you can track.

Both bands read your heart rate and HRV day and night. HLTH also lets you tap for a live heart-rate reading whenever you want one, and charts your average heart rate day by day.

Hume tracks heart resilience alongside your HRV and recovery, and plots it over weeks and months.

HRV is the tiny variation in time between heartbeats. The more easily your body switches from stress to rest, the higher it tends to sit.

Follow it through a season and you can see whether your heart is getting fitter.

HLTH uses HRV to answer the next-day question: did you recover overnight, and should you push hard or ease off today? That's useful, and on training days it's often all you need.

What it means for you: a resilience line followed for a year shows whether you're getting fitter, and Hume builds that line for you.

Blood oxygen tends to dip at altitude and can shift with how well you sleep.

Skin temperature shifts too. It moves across a menstrual cycle and can stay up after a punishing week of training.

Neither number means much on its own. Once the band knows your normal range, it can show you when you've drifted out of it.

On Band 2.0, both are core metrics, read all day and all night.

HLTH takes a blood-oxygen reading every hour, day and night. Its feature list and tech specs don't mention skin temperature at all.

What it means for you: blood oxygen and skin temperature show how your body is coping with poor sleep, long-haul travel and hard training, and Hume follows both around the clock.

A 24/7 band only works if it stays on. Band 2.0 carries an IP68 rating and is good to 1 metre for up to 2 hours, and Hume says it's fine for showers, swimming and workouts.

HLTH's band carries IP68 and 1 ATM ratings, which cover showers, sweat and rain. HLTH's own FAQ calls it water resistant and says it isn't made for swimming or diving.

Charging is the other time a band comes off. Band 2.0 needs somewhere between 20 and 80 minutes on the charger, depending on how flat it is; HLTH quotes 90 minutes from empty, though a 10-minute top-up buys about 3 days.

What it means for you: if you swim, a band you have to take off for the pool leaves a gap in your data several times a week.

HLTH wins on price, battery life, hourly blood pressure and workout tracking. Hume Band 2.0 takes swimming, skin temperature and the ageing side: metabolic scores, biological age and strain alerts, all free in the app.

HLTH quotes up to 30 days with typical use. Hume's figure for Band 2.0 is 14. If you hate charging things, that counts.

Band 2.0 needs the charger about twice a month, and each refill is done inside 80 minutes.

What you get for the extra charging is a band that reads heart rate, HRV, SpO₂ and skin temperature continuously, plus an optional Premium tier with an AI health coach.

All of that feeds Hume's ageing scores, and HLTH doesn't list an equivalent. HLTH puts its effort into the here and now: hourly blood pressure, four stress levels, cycle predictions and 30+ sport modes with connected GPS.

Wear either band for two years and you'll have hundreds of nights of sleep, stress and heart data.

On Hume, that history also feeds your Biological Age, so you can see which way it moved.

If you mainly want a cheap, light band that lasts a month, costs nothing after you buy it and charts your blood pressure every hour, the HLTH Band is good value at £79. It weighs 18 g, logs stress and sleep, and you'll rarely see the charger. For that buyer, I'd say go for it.

If the question that bothers you is whether you're ageing faster than you should be, where your metabolism is heading and whether last month's habits helped, HLTH doesn't list an ageing or metabolic score to answer it. Hume Band 2.0 covers all three using light-based sensors much like HLTH's, inside a free app:

✅ Metabolic Capacity

✅ Metabolic Momentum

✅ Unusual-strain alerts

✅ Biological Age

✅ Pace-of-ageing tracking

✅ Cardiovascular trends

✅ One Health Score

✅ Continuous SpO₂

✅ Skin-temperature tracking

Every one of them comes free in the Hume app.