When at home - pushups, pullups, situps can be done right next to your computer. If you are in an apartment - use the stairs rather than the elevator. If you need to go to the store - walk if possible.

I went back to the office. I immensely enjoy the amount of stuff I don't have to deal with, like lunch, coffee, cleaning and whatever may pop up.

Good observation that is relevant for the entire industry. Fitness is roughly a derivative of time and intensity. Seems like you have a good amount of low intensity (walk 1hr). Adding in some strength work would go a long way towards preventing muscle atrophy. Pavel from Strong First has a “grease the groove” method they calls for intermittent low rep - high intensity strength that works well IMO - https://www.strongfirst.com/

1 hour long walk and 3 hours of other stuff is already plenty I think. It's not like you're bed-ridden and can develop bed sores or other conditions. Even if working in the office, most of the office time is spent sitting in-front of the computer anyways.

At least in my office, one can't just walk around freely since that will disturb other people unlike in a home office where-in one can walk around or stand-up briefly when one feels like it.

I got some sandbags (one 12.5kg and another 22kg) and they have been really fun to use. Unlike dumbbells that can be grabbed in only so many ways, sandbags have a bunch of different handles on them allowing one to do bicep curls, bent-over rows, squats, military presses, deadlifts, etc. What I also really like about them is that, unlike dumbbells, they are soft and won't dent your floor or make much noise if dropped. Resistance bands, a pull-up bar, and TRX-like suspension systems are great options too, but I find the sandbags more fun and versatile.

But while strength training is great for maintaining muscle tone, I find that in small quantities (below the point of breaking a sweat) it doesn't quite offset that feeling of sluggishness in the body after a long day of sitting. Jump-rope, jogging, and biking are nice because they get your heart really going. But best of all is rowing because it's a full-body, low-impact-on-joints activity with a wide range of motion, and you can vary the intensity easily by adjusting your amplitude and strokes per minute.

Get yourself a standing desk and alternate between sitting and standing.If you want to take it to next level get a underdesk treadmill

This advice appears to be downvoted - can anyone suggest why a standing desk is not a good idea?

It is a good idea, I actually use a dresser for my workstation at home and I’m always standing like I was at my standing only desk at the office.

I find that it takes about a year to transition to standing only during work, especially when you’re used to thinking deeply while sitting, but it has been a huge help to my productivity and it dramatically lowers the energy barrier to go in to do some walking or a quick physical activity to keep the mind sharp.

Be more productive is nice, because then I just take all that extra time and use it to help around the house or go on walks outside myself.

i spent from 15 to 29 sitting down. it took a terrible toll on my health. i smoked cigarettes too.

get some hobbies and things to do that require you to be active. also get a dumb bell that is a good weight for you to start, maybe 10lbs. and break up your thinking bits with some workout bits. throughout the day. do some pushups, situps, that kind of thing.

its important to not neglect your physical health.

I have the opposite problem. When I was WFH I had time and energy to exercise, and generally eat healthy home cooked meals.

Now that I’m back to the office, between work and the horrible commute I am too exhausted to exercise, and I’m eating a lot of junk food again.

Lost 20lb in 2020-2021 WFH. Gained nearly all of it back now.

I don't move as much as I should :( Long walks, stationary bike and some yoga - and it is way to little. This is one of the reason why I switched jobs and I started to work for a company that has hybrid model.

If you like gaming, a dance pad and Stepmania is a fun, awesome, and cheap way to get some high quality cardio.

Playing on easy modes is like walking. Once you build up some skill, playing on hard modes can feel like sprinting.

I got an under desk treadmill. It's flat (no bar up front) and only supports walking up to 5mph. I've been regularly putting in 15,000+ steps on day that I work.

A standing desk also helps to alternate from sitting down.

I find it gives pressure on low back after few min

Gotta move around more is the only answer. Refill your water, walk around your place or outside your place, etc.

If you just want more diversity, reading a book seems like an easy option. Otherwise like some comments mentioned, bodyweight exercises are good. 1-2 hours of those a day should be fine if you are doing them seriously. Look up on youtube if you need specif exercise suggestions.

Stand up for some meetings (like standups?)

Every 2 hours take a 15 minute break where you go for a walk outside

So that's a different problem - it sounds like when you were in the office, you were able to make time for those things, but now you don't. Maybe you would need to take a bit more control over your schedule and block out time for exercise and breaks.

If you're not able to do that, there are a few options, such as taking calls on a headset while you're out walking, or using an exercise bike during a meeting.

If every single meeting you have requires your full, undivided attention and contribution, that's a red flag for me that you're likely overstretched, and there's a big 'bus factor' risk. How are those meetings handled when you're on leave?

Exercise