Because if you need to fit 560 minutes of cardio and then also fit weight lifting 3 times a week that's a lot of time working out
With small/insufficient muscle size, you simply run out of stored glycogen before you get tired cardiovascularly.
> Because if you need to fit 560 minutes of cardio and then also fit weight lifting 3 times a week that's a lot of time working out
Proper exercise is absolutely a lifestyle change and a big commitment. Not only do you have to exercise several hours a week, but also eat healthier macros and fix your sleep to make sure most of the benefits stick and aren't wasted.
People try to half-ass it all the time by doing weird diets or going on 15 minutes walk during their lunch break, and yes it's better than nothing, but not by much.
Like my heartrate for sure goes higher when lifting weights than when I walk. If I walk fast, it might get closer, but I am not that confident.
300 minutes of HIIT per week are equal to 10 HIIT sessions per week, I would argue that's outright impossible, the body cannot handle that, I don't think even an Olympic athlete can handle more than 3 times per week HIIT.
Vigorous might be possible, that's still 5 times 1 hour cardio sessions, on top of which you have to add 3 sessions of weight lifting for bone density, on top of which you have to add balance training and stretching.
There isn't enough time in a day to do that if you work, let alone if you have kids
Vigorous would be Z2/3 cardio, so like 120-160 BPM for most adults. Moderate would be Z1 90-120.
Once you are capable of doing cardio consistently in Z4/5 with HIIT and tempo training you really don't need to worry about "am I doing enough exercise."
You can eat carbs during cardio ("fueling") though it's unlikely an issue doing 600 mins a week. Muscles store 15g of glycogen per 1kg (more for trained athletes) , which amounts to 60 (k)calories. In aerobic process with COP ~ 25% these nicely convert to output energy of 60 kJ. To produce this much output over 90 minutes you need to push power of ~11 watt. Elite athletes have FTP (functional threshold power) around 6 w/kg. It's over the entire body mass, not just muscle, but even if you are pushing 50% body fat, you can be pretty confident you have enough glycogen for 90 min of aerobic exercise at your FTP (also liver holds/can produce on demand quite a lot of glycogen and aerobic process will use fat for energy as well). Even if you do 200 minutes 3 times a week instead of doing 90 minutes every day you can get by staying in under 3 w/kg power zone, which is still greater than most people's FTP (and even fewer people can hold this power over 3 hours).
In my own experience, no. Strictly cardio. The number of squats you'd have to do to constitue even five minutes of vigorous activity is practicably impossible.
Lifting weights could certainly count/classify as moderate activity though, just without as much 'bang for your buck' as dedicated aerobic exercise.
... I mean that seems kinda orthogonal. No-one's requiring you to do weight training three times a week.
(But no, it presumably wouldn't count)
