I'm in my mid-40s and I do cardio 3x weekly, and during my sessions, it's basically HIIT training. I try to keep my HR above 150 during my sessions, but it peaks in the low 180s intermittently.
Is this okay? My doctor noted potential concerns with getting my HR up that high, but it could be fine, she wasn't sure. I don't get any dizziness or anything (generally that happens if I sustain a heart rate above 185 for a bit). I'm not staying at 180 bpm, that's just the peak, I'm targeting an average HR of around 150-155 for my workouts.
In a 60 minute workout, I'll probably spend 10-15 minutes with my HR between 166 and 182 range.
Not sure if I should scale it down a bit or take it easier, or if this is fine.
Have you determined your max heart rate (HRM), and if so, how?
HRM is highly variable among individuals and calculators based on age etc are a waste of electrons.
If you know your HRM (and if you're not puking while finding out, you're not there yet) you can calculate your heart rate reserve which is the difference between resting and max.
I'm a 60 year old runner. Speed work and tempo sessions will put me up in your range for up to 30 minutes at a time. Interval work will put me over 90% for a couple minutes with a minute or two of cooldown between peaks.
Generally it's not a problem. Your body won't let you work hard enough to damage it (lots of caveats here from cross-fit people who somehow manage to develop rhabdomyolysis). You will develop loss of willpower/overwhelming exhaustion before you can work to your limits. If you are just getting active then yes you can injure yourself easily, but probably for different reasons.
Big caveat here You can train to ignore your body's signals. Cross-fitters do it, free divers do it, endurance swimmers do it, and lots of others. If you are one of those people you can absolutely hurt yourself to the point of death. But if you are not explicitly training to ignore your bodies safety signals you should be fine.
I haven't gotten my VO2Max (I'm not a runner or anything, and not sure how to test otherwise), but I've done one or two workouts where I pushed as hard as I could and my HR peaked at 190, wouldn't go higher. At that point I got dizzy and lightheaded, so I'm assuming that's my max. I seem to be fine up to 185-186, just heart pounding and out of breath after a short time at that pace.
Anything between 150 and 160 I can pretty much maintain, maybe not indefinitely, but for a comfortably long duration. And my resting heart rate seems to be around 48-50 overnight during sleep, and in the low-to-mid 60s if I'm just relaxing.
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Edit - regarding your edit/caveat, I usually still have gas in the tank, so to speak, after my cardio sessions. I could keep going in most cases, but I’m not trying to hurt myself, and a 60 minute workout (my usual length) seems good enough.
My weightlifting workouts by contrast seem easier during them and my heart rate stays low, but after I wrap them up I feel completely gassed usually.
I've never had my VO2max done either. I relied on Jack Daniel's VDOT tables which take a race time and work backwards to estimate the VMax needed for the time. For runners the HRM estimate came from running hill intervals. Find a nice long moderately steep hill - it should be a 1-2 minute sprint up. Then start running. Do a little 2 mile moderate pace warmup which ends at your hill. Sprint up at 100% perceived effort, jog down, and do that until you're vomiting. It's usually 4-5 reps. Whatever your peak was would be within a few beats of HRM.
Another question to ask is what device are you using for your heart rate monitor?
Chest straps are the gold standard, some wrist straps are reliable, and I’d be dubious of max hr readings from a wrist watch. They tend to get caught reading your cadence as a heartbeat, and it can cause some weird fluctuations.
Then, as described above, your next step is to understand your max heart rate. The typical formula is 220-age, but I’ve found that it can definitely miss the mark. I’m 40 and had my heart rate hit 195 on a 5k race this past year as I was booking it towards the finish line.
Finally, it helps to know if there are any underlying cardio respiratory issues that would impact the strength of your heart.
I would say, in my situation, there’s little to no risk of hitting the 180’s when my max is in the 190’s, I can go that fast without causing joint pain or injury, and I have no underlying issues that would exacerbate my risk. Everyone’s different, but if you check those boxes too, then I’d say you should be fine.
Could be it's the watch, it's a Garmin Vivoactive 6.
I've ignored one-off high readings that only last for like a second spike, I'm going by specific heart rates that I peak at and sustain that I can monitor for a few seconds even if I stop moving.
Same, and by that metric I'd be dead. 😂 I've hit 190 bpm, and regularly get into the 180s, but standard metric would have my absolute max in the 170s. I can sustain 170 bpm for several minutes without even feeling too stressed.
No issues there, good heart health. Occasionally high triglyceride profile (depends heavily on what I eat the day before a lipid panel) and frequent slightly lower than optimal "good" cholesterol on my lipids, but that's about it. Overall cholesterol is low, and my doc gave me a clean bill of health with my heart (literally saw the doctor this morning for my annual checkup, awaiting my blood work later this week).