does walking 15k steps genuinely make you lose weight to the point of being worth it. Going on these walks everyday is taking up so much of my time and I am so miserable but it is the only way i feel i am allowed to eat.?! if I were to stop would it make me gain weight quicker?
Hi there
To get the most benefit of the fat burning zone 2 cardio, would you say it's better to do 45-60 min straight (after weight lifting like I normally do) then two separate sessions of 30 min each?
Thanks
Hi.
I bought a Polar sensor, so I can take a look and try to keep on zone 2 HR.
Would you guys consider this zone 2 level training looking at this numbers? It was on Assault Air Bike.
I'm 39 and I'm not sure about my max HR, but rested is around 40/44.
Thank you.
I (66M, 6’1”, 270 lbs) am scheduled to begin taking Zepbound at 2.5 mg. One of my primary motivations for taking Zepbound is the assumption that if I was carrying a lot less weight I would be a faster swimmer, walker, and bicyclist. However, reading this sub it seems like it may not be so simple as lower weight = faster times. Am I about to be disappointed about performance gains?
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68 years old. 50+ years of recreational endurance training on bike, rowing, running & Precor AMT. No more running because hip replacement 3 years ago.
Been wearing a Polar H10 chest strap with ECG app designed for Polar H10. PACs (burden ~1-3% w/couplets); PVCs burden <1% but with a few 1 to 8 second runs if NSVT.
Atrial flutter (not afib) ablation 9 years ago.
Zio Patch & Boston Scientific patch over last 9 years similar results.
No documented afib.
SPECT myocardial stress test: 143 bpm (93% predicted max) with PVCs and PACs including couplets.
Echocardiogram: Enlarged left and right atrium (53 "severely" dilated); EF 58% rest & 57% stress. "No significant fixed or reversible defects."
hs-Troponin elevated after workout (38 - 40 -45 - 40 - 35).
EP says CCTA & Cardiac MRI/LGE not necessary. But to give me "piece of mind" regarding fibrosis/scars, he ordered CMR/LGE. No results yet.
EP said I'm cleared to resume long cardiovascular workouts (2+ hours). He said my PREVENT score was 4.1%.
So, I'm still doing the long workouts while wearing a Livenpace ECG monitor which has detected PVCs (burden <1%) including a few runs of 1-8 seconds of NSVT (also on my Zio Patch from 9 years ago); PACs (burden 1-3%) including couplets; SVT (few seconds); no afib, no aflutter.
But, because I know about these arrhythmia, I am experiencing some periodic chest tightness at rest. Trying to determine if it's a result of health anxiety (aka cardiophobia) or something heart related.
EP says: Go for it. No restrictions.
Any thoughts. Any recommendations. Any similar experiences?
Thanks in advance.
68 and want to keep at it a bit longer. 😀
Hi everyone,
Due to my schedule it is very difficult for me to do 3 days of cardio per week. What are the pros and cons of doing 3 hours of zone 2 cardio once per week?
addendum - I guess my schedule is not the only thing making me want to do all my cardio in one day/week. I live in England. No car, lots of walking. Car is not a necessity right now. If I go to gym and only lift (even on leg days), I still have a lot of energy to do my daily stuff. But if I do cardio (even 45 minutes zone 2) I am fine in gym but after gym I don't have much energy.
that's why, I want to do do all my cardio on the same day (Sunday) and get over with it for the week.
Thanks
I pulled validation studies on how accurate each device's VO2 max estimate is across multiple wearable brands and any claims the brands make on their accuracy into a comparison chart. It's broken down into how each device measures VO2 max, what the company claims, and what independent studies actually found. Sources linked as well for each row if you want to check these out further. Hope you find this helpful if you're tracking it!
If the tables are difficult for mobile readers I'll also include a mobile first page with the data in the comments if you need it.
| Device | how it estimates | company accuracy claim | Independent validation | Source |
|---|---|---|---|---|
| Garmin (watch) | Exercise via heart rate vs pace on a run | 95% accuracy and errors under 3.5 ml/kg/min | Best validated of any wearable. MAPE 7% (fenix 6) and 6.7% (Forerunner 245) but underestimate highly trained runners by 4-5 ml/kg/min | Carrier et al. 2025 & Engel et al. 2025 |
| Apple Watch | Exercise via outdoor walk/run/hike | None published | Two studies, both show it underestimates MAPE 13.3% and 15.8% | Lambe et al. 2025 & Caserman et al. 2024 |
| Polar | Via resting Fitness Test (HR + HRV) or a run test | Marketed as a validated non exercise estimate | Resting test overestimates (+2.2 ml/kg/min) and a CPET study found MAPE 13.7% | Neudorfer et al. 2025 & Molina-García et al. 2022 |
| Fitbit / Google | Via resting HR & profile, refined by GPS runs | None public | Consistent as a score but overestimates the absolute number (52.5 vs 49.9 in lab) | Freeberg et al. 2019 |
| Samsung Galaxy Watch | Exercise via outdoor run | 82% correlation vs clinical equipment (company funded, Univ. of Michigan) | A study only validated its heart rate during a max test not VO2 max | Inoue et al. 2026 (HR only) |
| Whoop | Proprietary, passive & GPS run model | Internal MAE 3.7 ml/kg/min, MAPE 8.0%, r 0.90 vs a metabolic cart (n=248) | None independent | WHOOP (vendor) |
| Oura Ring | Initial reading via profile data more accurate via guided inapp 6 minute walk test | No accuracy figure published (vendor states it is less accurate than a lab test) | None independent | Oura (vendor) |
| Coros | Exercise via heart rate vs pace (unpublished method) | No figure published (vendor claims "very close to lab") | None independent | Coros(vendor) |
| Suunto | Exercise: same Firstbeat engine Garmin uses | Inherits Firstbeat (95%) | No Suunto specific study but rides on the same validation as Garmin | via Firstbeat |
If I missed any studies please feel free to let me know!
I recently added rowing machine to my cardio but very confused by how much calories it burns based on my Apple Watch estimate 😅. I know it’s not very accurate but still want to understand the reason behind it and if there is a better way to estimate it.
Two examples from recent two sessions:
Obviously rowing was a lot harder with much higher HR. But how come the estimated calories are the same… When apple does the estimation they should use all these metrics, I would anticipate there should be a difference but maybe I’m missing something? Thank you for any tips you might have!
I only have a limited amount of time for cardio (3x/week), so I tend to push hard every session. Today was an uphill / downhill hike.
Is it better to stay in zone 2?
Or does that only apply if I had more time/session or more sessions, zone 2 being easier to do longer and to recover from?
Right now I've been doing cardio for about 20 minutes aiming for about 155 HR the entire time but just recently learned about low intensity cardio and that should aim for around 130-140 HR for fat loss. Apparently 160 HR burns more glycogen? Im just confused. Does anyone know how much should be aiming for if I want to lose fat and maintain muscle? I'm doing cardio after every workout 5 days a week
I have been strength training for a few years now but wanted to add some cardio into the mix. I lose my breath very quickly on even a slight incline walk. All cardio I have tried so far puts me at my max heart rate (180bpm) within a minute of starting. I am trying to incline walk at 8% at 3.5kph and I am slowly lasting longer (so far can do 1km, about 17 mins), but is this the best way to improve cardiovascular health by sitting at max heart rate?
The thing is I am not puffed at all, I am not desperately trying to catch my breath, but my heart rate is just max almost instantly. Should I lower the incline maybe or should I stick to doing what I am doing to get fitter faster? Any suggestions would help, thanks!
Hi everyone,
I’m looking for some perspective on a recent clinical stress test result.
For context: I’m a 33-year-old male, 6'2", 190 lbs. Aside from general yardwork, I haven’t done any structured running or intense cardio in about 10 years (I used to trail run back in the day).
I recently had a medical stress test done due to some palpitations. The cardiologist told me my VO2 max was 65, noted it was "quite good," and cleared me regarding my heart health. Honestly, I’m skeptical, it seems remarkably high for someone who hasn't trained in a decade. My resting heart rate is also consistently in the 40–45 bpm range, which further confuses me given my lack of current activity.
Is it possible for a clinical VO2 max score to be inflated, or could there be another reason for these numbers? I only reached 98% of my predicted max heart rate during the test, not the full 100%.
How do these clinical numbers correlate with actual fitness for someone who isn't currently a runner? Is 65 actually a "good" score, or am I fundamentally misunderstanding how these are calculated?
Thanks for any insights!
For someone new to running, how do you train to improve your time?
After work… In the sun, heat, humidity… played doubles tennis and was shocked that there was this much Zone4 and Zone5.
I’m grateful every day that my body does what is asked. I know one day, will be the last it’s able to do what I love to do.
My Vo2Max is very high for my age/weight.
This happens 3-4x a month. Most workouts stay Zone 3, dipping into 4.
I'm a late 30sf and I've been running 5ks and 10ks very slowly for 2.5 years. My run pace is about a 13 min mile. However, this pace is an all out effort for me and my heart rate stays > 175bpm 95% of the run.
I want to start zone 2 training but the only way I can maintain a zone 2 heartrate is by power walking and I do that for 30-40 min. My zone 2 heart rate is 108-126. Is this normal?
Is my training plan below the correct way to train in zone 2?
Mon, Tues and Thur - 40 min powerwalking in zone 2
Saturday - run my normal 5k or 10k at 13 minute mile with a heartrate of 175-182
I don't do any other exercising.
I have been running for about 20 years but more for fun, to explore new places, or zone out mentally than racing. Recently, I got a HRM and what I had thought was moderate effort ends up being in max zone pretty much all the time. Which isn’t great. Long story short, I want to figure out a cardio running and/or walking routine to figure out what’s normal for me and that will help drive improvements over time. Most coaches seem focused on time/distance goals, which obviously are correlated, but I would like someone with experience and understanding of heart health and training as well as running mechanics etc. Does anyone come to mind in the NYC area (pref Brooklyn)? Thanks to everyone!
Hi I'm just wondering if I was doing too much cardio recently, I've doing 30 minutes of walking everyday at around 3.5mph for a distance of about 1.60 km everyday, on a treadmill. Some of my friends think this is too much but I don't feel overworked or overstressed. So am I doing too much cardio?