Is zone 5 safe?

[freshin]

I’m very overweight I guess I’m classed as morbidly obese. I was 18st 11lbs and after 2 months of diet and exercise am 17st 6lb. I walk at varying inclines on the treadmill and feel I am getting slightly fitter. My watch records my heart rate etc. I do use other machines and these include resistance work.

I recently pushed myself further than before and I noticed for the first time I was in zone 5. A friend told me it is actually very bad for you to be in that zone as you stop losing fat and begin losing muscle. I’m not sure if this is true. Happy to receive opinions and advice.

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Respectfully, your friend is talking bollocks.

Zone 5 means you’ve pushed yourself to your limits (so up to 100% of your maximum heart rate). That’s good! Your fitness will improve. Keep up the good work. And tell your friend to fuck off. 😛

No it’s not bad for you. Each zone has different benefits and effects on the body.

The ‘best’ zones for pure weight loss are 1-3 as that’s when the body essentially uses fat as fuel, whereas zones 4-5 have different biomechanics. But it’s likely in an all-round workout, particularly one with intervals etc, you will hit all the zones. Zones 4-5 are great for cardiovascular health and boost your metabolism even when the workout is over (afterburn effect). And exercising isn’t just about weight loss, it’s about fitness and longevity and all the zones play a part in that. All pieces of the puzzle! All movement is good movement.

It’s fine, friend is on the bull shit wagon!

Gatecrashing this o e. I have a Fitbit and I’m sure it only has 3 zones: moderate, citrus and peak. Please can I ask what devise you’re using for 5 zones? Any extra in for from anyone else too on what they mean or how they relate to the Fitbit zones?

@KarmenPQZ I think the 5 zones are a universally accepted thing. You can track them on both Apple Watch and garmin. You can also work them out yourself with an online calculator.

@freshin your friend is talking nonsense. While you probably shouldn’t aim to be in zone 5 the whole time you’re exercising unless you’re really pushing yourself in a race or something. If you are exercising and really exerting yourself then you’ll be in zone 5 for a bit at least.

when I first started running I would be in zone 5 for most runs! Now I’m fitter I spend a lot less time in zone 5 but may still dip into it on hills on a normal run or be in it pretty much the whole time if it’s a 5k or 10k race. Longer races I don’t go as fast so would be in it less.

don’t stress to much about zones. Zone 5 just means that you’re in anaerobic exercise rather than aerobic. It will help to build fitness.

As previous posters have confirmed it's safe (although probably not that comfortable!) to be in zone 5 at some points during exercise. I aim to dip in and out of zone 5; or the defibrillator zone as I call it 😁 during Spin classes

It's great for your heart to hit zone 5 occasionally! You'll also see yourself getting fitter. In a few weeks, you'll be able to do the same workout staying in zone 4

I’m using an Apple Watch

Well a lot of my runs would be very unsafe if that was the case.

I wouldn't worry OP. It’s your heart working out.

Congratulations on the getting fitter 🙌
It’s not easy!

I know that zone 2 is best for fat burning but I think HIIT workouts are best for metabolism and overall calorie burn (plus increased fitness). Can you start to mix it up and do some interval sessions (going up to zone 5 for short bursts) and some longer more steady zone 2 or 3?

Zone 5 for short bursts (eg 20-30 seconds) and then resting for a minute or two, and repeating 3-6 times, is the start of sprint interval training. (After a warm up) This is really good for improving vo2 max and stamina.

before I knew about any of that, many years ago, I used to do short skipping sessions of 5-10 mins (often with rests in between sets of 100 jumps) and it would completely kill me. But it really improved my overall stamina for running and the martial arts I was doing at the time. I now know it was probably hitting zone 5.

I taught myself tabatas this year, slowly building it up. They become rather addictive!

This is what my Samsung health app says. Being in the maximum rate band is ok in short bursts