Indoor rowing: Does not reqire to much space, can also be done outdoors, and provides a full body workout with variable intensity. 20 minutes every other day can be enough to get/stay in shape.
I strongly recommend that anyone with a spare bedroom own a Concept2 rower. You can put thousands of km on them without replacing a single part. Nothing beats the consistency.
If you can find the discipline to do 5+km/day, you probably don't ever need to go to the gym. There are a few movements that would be beneficial as a supplement, but you can use bodyweight for most of those. The simple pushup gives you about 80% of the missing picture. I typically do a 5km row and then 2-3 sets of pushups and call it a good day.
I strongly believe the barbell squat is the best exercise by miles. But, its the biggest pain in the ass in terms of logistics. Rowing feels like a really happy compromise, especially considering the continuously-variable intensity and the mechanism of action.
Concept2 are the gold standard of indoor rowers. You can find them used for cheap and they are built to last a lifetime. There are tons of rowing program channels on YouTube to follow and keep it interesting.
If you can find the discipline to do 5+km/day, you probably don't ever need to go to the gym. There are a few movements that would be beneficial as a supplement, but you can use bodyweight for most of those. The simple pushup gives you about 80% of the missing picture. I typically do a 5km row and then 2-3 sets of pushups and call it a good day.
I strongly believe the barbell squat is the best exercise by miles. But, its the biggest pain in the ass in terms of logistics. Rowing feels like a really happy compromise, especially considering the continuously-variable intensity and the mechanism of action.