Your body is fairly important, so I'd suggest spending more than 7 minutes on improving it. If you can't, fix your priorities. Don't try and "hack" your workouts for the purpose of reducing how long they take.
And beyond that, the 7 minute workout is mostly useless. Go to the gym and lift weights 3-4 times a week (and then lift heavier ones the next time, repeat). It's not complicated.
The 7 minute thing wasn't so much about time (I think that was just the sales pitch) - it was promoting the HIT (High intensity training) school of thought.
Some research is pointing that, for some proportion of the population, short bursts (i.e. a few minutes) of very intense activity is either as effective or more effective than long periods spent in the gym etc.
The big caveat seems to be that response to a) HIT exercise or, b) hours at the gym in general, has a genetic component to it.
I don't see how doing this for seven minutes is going to hurt anyone who sits on their ass all day and does nothing.
If anything it is good because it gets you started. Start doing these 7 min a day workouts and eventually you work your way up and are at the gym doing full workouts.
Do you have any data to prove that 7 minutes is insufficient? Seems like the people proposing this did their homework; it's only fair to expect you to do the same.
I am on the crazy side of the spectrum, currently training 10+ hours a week to do triathlon + powerlifting, but I think a more sane person could get a huge benefit in maybe 5 hours a week. 7 minutes will do something, but I would love to see any 7 minute a day workouter in as good of shape as a 5+ hour workouter.
I do disagree that the ideal workout is go to the gym and lift weights 3-4 times a week. Gym is good, weights is good (I do them), but cardio is also super good. Most studies about exercise makes your memory x% better, or exercise makes you live y% longer are about cardio.
Ways to try and get both?
a) 4 days of 1 hour of crossfit type exercise would work (not my preference)
or
b) 2 days of weights for about an hour, 2 days of cardio for about an hour, and a decent amount of walking on off days.
The point of the 7-min workout isn't to keep you in as good of shape as a 5+ hour workouter, the point is to get 90% of the health benefits in a minimal amount of time as the 5+ hour person. The 7-min workout is designed for the busy professional concerned about their health. If you want to run triathlons, you still are going to need to slog it out doing training workouts.
I would be astonished if 7 minutes per day provided even a measurable percentage of the benefits of exercising 5 hours per week (say 3.5 hours lifting and 3 30 minute runs).
The nytimes article listed in the parent, which is what sparked the 7-min workout craze, discusses and links to the study. I am not going to get into too much detail, but the general idea is that working a bunch of different muscle groups at high intensity for short periods gets you most of the benefits of longer endurance based workouts.
I have a very similar training regimen. I train twice a day. Morning and evening. What I do depends on how I feel and weather. It comes out to probably 14+ hours a week. I either do weights (squats, cleans, etc) or run or walk with a weighted vest (40 lbs at the moment) for 3 miles.
As long as I eat and sleep enough I feel awesome and have tons of energy and mentally I feel better. In fact, I felt better mentally and physically when I started doing 2 a day workouts.
Everyone thinks I'm insane and say it's not possible without drugs. At first it might make you feel a little drained, but you build up to it over time if you stick with it.
The human body is capable of amazing things. You don't have to treat it like a thin shelled egg when it comes to exercise.
I would frame it slightly different; if you can't spend more than 7 minutes improving your body, keep searching & find the thing you can spend more than 7 minutes on.
The process by which you do this is important, by the way. Don't lounge on the internet looking for the most feel-good workout that talks about your chakras, alignment, and generally promises returns for no work. Do collect a grab-bag of activities (weight lifting, soccer, rock climbing...) and try one for 1-2 weeks as if you were serious about it. Then see how you feel about it, and if you don't like it after a few weeks try the next thing.
And beyond that, the 7 minute workout is mostly useless. Go to the gym and lift weights 3-4 times a week (and then lift heavier ones the next time, repeat). It's not complicated.