After a long period of sloth, I am trying to get into something resembling good shape. I am doing both cardio exercise and weight lifting, but this question is focused on the cardio.
I am 26 years old, 6’2", about 220 pounds.
I have bought a rowing machine. I like it quite a bit.
So far, I am doing 20 minutes on the machine 5-6 days per week. Currently, my average power output according to the display is 150W. At the end of the session, my heart rate is about 155 bpm. According to some calculators I have seen online, my maximum heart rate at my age is 195 bpm, and the target range for best results from exercise is from 55% - 85% of the max (105 bpm to 160 bpm, roughly).
(incidentally, my resting heart rate is around 70. I’d like to get it down to around 60 or lower, but that is a tangential goal)
So far, I have been gauging my progress by how high I can keep my power output over the course of the 20 minutes. I started at around 90 W for 12 minutes and have worked up from there. I have not paid much attention to heart rate until recently.
My question is: for maximum progress, efficacy, benefits, etc., should I continue what I’m doing (exercising at pretty close to the upper range of the suggested heart rate (85%) for a shorter period, e.g. 20 minutes), or should I try to reduce the intensity so that I can sustain a lower heart rate for longer (e.g. 30 or even 45 minutes)?
I guess there is a third option - try for a longer duration at the same intensity (i.e. 30 minutes at 155 bpm). I feel like 20 minutes is about the most I can tolerate at 155 bpm, but if there is a benefit I guess I can force myself to push it…
Resting heart rate will go down as you improve fitness.
Calculated max HR is only an estimate. While close for most people, there are outliers.
55% is too low. You should be able to hold 70% for a considerable time.
Lower intensity for a longer time will result in more calories burned total. The myth of a “fat-burning” zone is just that-a myth.
You can double(once you’re trained for it, work up gradually) the distance/time by only slowing pace by 5%.
I am interested solely in improving fitness, not burning calories or losing weight. For the purposes of this question, anyway.
So, I am currently doing about 80% of max HR for 20 minutes. I feel like that is close to my limit at this point, although I guess I could push it. Will I improve fitness faster if I try for 70% or 75% for 30 minutes?
Depends on your fitness needs. Generally, longer duration is what most people are looking for. However, sometimes you need higher intensity/shorter duration.(boxing, wrestling, middle distance running)
You might consider going much longer at lower intensity one day a week like distance runners do.
Or all of the above and others, i.e. mixing it up. An occasional long slow is standard , and adding that to what you are doing would be fine, as would some slightly less intense than your current pace and a bit longer, but once you have a solid fitness base more important is adding some interval training of various sorts as well. What you are doing now is pretty much the “time trial” part of that linked list; throw the other 4 (long intervals, short intervals, power intervals, and fartleks) into your mix too.
I agree with mixing it up. You are going to be training different muscles by doing some occasional very high intensity workouts than you will just doing long but lower intensity workouts.
As far as cardiovascular health is concerned, most doctors recommend that you just focus on the lower-intensity, longer workouts, as that seems to be where you get most of the “general” health benefits.
However, I have read some research that exerting yourself to your absolute maximum limit for 2 minutes, a few times a day, has the same effect health-wise as doing a 30 minute lower intensity work out.
So really, whatever you do, is going to be good for you. Why not mix it up, just because it’s more fun, and you’ll be sure to be hitting everything you can.
I enjoy a nice long slow jog, for example, but I also like to sprint as fast as I can for about 2 minutes.
I’m in the mix it up camp as well - I would suggest a longer session once a week and HIIT (High Intensity Interval Training) sessions a couple of times a week (20 seconds max exertion, 10 seconds rest x 8 - only four minutes, but you should almost not be able to stand up at the end). The HIIT sessions are good for both aerobic and anaerobic capacity.
I don’t tend to look at my power output - I go by pace and aim for a sustained ~ 2:00/500m (or under 1:40 when working for HIIT sessions).