These are my (beginner) notes on physical exercises: covering exercises at home, with no or little equipment, without a diet beyond generally aiming to eat somewhat healthy food. With the aim to be reasonably healthy and in shape, but not bodybuilding or powerlifting.
Regular exercises are suggested by dietary guidelines, CDC, WHO, and The Wombles: for an adult, that's at least 150 minutes per week of moderate-intensity aerobic activity (e.g., brisk walking), or 75 minutes of vigorous-intensity activity (jogging, running, etc), along with some strength exercises. Benefits of aerobic exercises are numerous and seem rather neat.
Subjectively, it does appear to work as advertised. Not listed in the Wikipedia article, but another benefit is that fit people tend to look better, and it is easier to pick clothes in that case: they tend to sit better, and even silly-looking ones look fine if a person wearing them is in a good shape (and a better posture does not harm, either). Then there are minor implied niceties, such as it being comfortable to run a few floors up the stairs while skipping every other step, not sweating on a hot day. The body in general appears to work better, too.
It may seem that it is a dull kind of activity which people engage into in a prison, but people tend to spend plenty of time on other dull activities, which are less useful, while the environment may be not that different from a prison in some cases. Besides, one can not stay focused and work on something fun all the time.
It may be hard to start, similarly to learning anything. People try to avoid both, finding all sorts of excuses; yet it does seem fairly easy once you start, especially once it is a part of a routine. Also as with learning, perseverance is important. It helps that exercising may feel like a computer game with slow XP grinding: somewhat addictive, yielding relatively predictable results after putting time and effort into it, and one may optionally learn its mechanics better to increase the efficiency. While sports, I guess, feel more like games of skill.
One can start by picking a few strength exercises, a cardio workout, and repeating that daily. Preferably while not eating too much of junk food, and maybe combined with some stretching.
For strength training, bodyweight exercises tend to be easy to do at home and without equipment. Squats, plank, push-ups (may be more convenient with handles), wall sits. Pull-ups and hanging leg raises if you have a bar. Sit-ups if you have something soft to lie/sit on.
For aerobic exercises, also at home and without equipment, perhaps the easiest is just to look up cardio workouts, possibly in a video form, for instance on YouTube: videos are good to learn how to do exercises you are not familiar with yet, and one could use those as a timer (since usually those workouts employ some kind of interval training, apparently). No shortage of video workouts with additional restrictions (standing-only, no jumps, low-impact, for seniors, sitting on a chair), either.
For nutrition, regular dietary guidelines apply. with a bit more proteins (instead of the regular 0.8 g per kg of weight, it is 1 to 3 for active exercising). There are calculators and specialized diet development recommendations, along with all the calorie and macronutrient counting business, but I think one can stay in an okay shape without much of that.
For stretching, it is also easy to find routines on YouTube or elsewhere. Many common stretches are borrowed from yoga (asanas, or yoga postures, which generally do not require any equipment), and yoga as exercise by itself should count as a moderate workout. A related seemingly nice practice is mindfulness. Sitting exercises are often demonstrated by instructors sitting in a way that is likely to be tricky at first, like Siddhasana (aka Burmese position, which can be employed during meditation as well), but I guess it does not harm to sit in an easier position instead, such as Sukhasana (e.g., simply cross-legged) or Muktasana/Ardhsidhasana. Maybe "quarter lotus", though different poses seem to be called that. A few stretching routines, which seem appropriate for beginners (articles and videos): "How to Start an At-Home Yoga Practice", "8 Minute Stretching Routine For People Who AREN’T Flexible!", "Fix your posture and reduce backpain | 10 Minute Daily Stretch Routine", "15 min Beginner Yoga for Balance & Stability", "30 min Beginner Yoga - Flexibility, Strength & Balance". And not a routine, but a set of arm balancing exercises: "Beginner Arm Balances".
Wikipedia, WikiHow, ExRx.net, Verywell Fit, The Fitness Wiki, and MuscleWiki provide plenty of information; more can be found elsewhere on the Web.
Clothes should not restrict movement, which is a nice properly of clothing in general. They should not be too tight, should be elastic (especially pants, underpants, socks; for t-shorts it is okay to not be elastic), which usually implies some blend of cotton and synthetic elastic materials (such as elastane; apparently often it is 95/5, but 80/20 for socks). Apparently some workout clothing materials (polyester, Lycra/Spandex/elastane) even provide wicking.
Long hair may interfere with movement and sight, as well as absorb sweat, make it feel even hotter during exercises, and be generally awkward. I make a bun, but another option is to braid it.
A secure and simple bun, using just hair ties (no pointy, heavy, or unusual devices), can be made with two hair ties: one is used for a tight ponytail, then the ponytail is twisted to form a bun, and secured with another hair tie, similarly to the first option from "How to Do a Quick and Easy Hair Bun", or "Fitness Hairstyle How to Tightly Secure Your Hair Bun", "How to Tie a “Man Bun” (Without Calling It That)". While using a finger to wrap the hair around it, it helps to take it out after the first loop, and then tighten the hair while holding it from the top; then the resulting bun is tighter.
A quicker bun is just to pass the hair through a hair tie (a loose ponytail), and then pass it again, without pulling all the hair out (leaving a loop): that's nice for cooking and suchlike, but not secure enough for a workout. That's called "the fold over" in "How to Tie Your Long Hair – For Guys (5-YR. ANNV. EDITION)".
Any bun should be tied tightly in order to hold well. The hair around a bun should be tensioned as well, holding the bun close to a scalp. They also seem to hold better when tied at the top, so that they are not shaken as much side to side by jumping jacks, running in place, etc.
It is individual and minor stuff that determines how to incorporate exercises into one's routine, but I went for exercising in the morning, and it takes me around 2.5 to 3.5 hours from waking up to getting out of the shower, having done squats, plank, pull-ups, stretching, an aerobic workout (25 minutes of interval training, then 15 minutes jogging in place), leaving a few more quick sets of strength exercises and more stretching for the daytime. Having a breakfast, skimming through Hacker News, Wikipedia articles, or other light reading, sometimes doing smaller work tasks, and waiting for the body to wake up, is included into that time. Reading and work can be major time hogs, especially if done between exercises, and a heavy breakfast is likely to slow you down (a full stomach suggests to wait a bit longer before exercising). Though waiting to wake up completely for an expected better performance or something along those lines can hog plenty of time without providing any real benefit: best to just go ahead and do the exercises. It takes about 1 hour for breakfast and bathroom, and 1.5 hours for exercises.
How long it takes to see exercise results is individual as well, but apparently it is on the order of months (or even weeks, especially in the beginning). Personally, after about a year (a bit more for anaerobic exercises, less for aerobic ones) and as an adult male, I reached 3-minute planks, 13 to 15 pull-ups in a set, went from weighing about 75 kg to weighing about 69 kg (at about 180 cm height), and generally felt more comfortable. Without paying much attention to the diet or having a properly planned routine, and just with bodyweight exercises; I think one can progress faster with a more thorough approach. The second year brought little progress, I mostly ecercised to stay in shape then.
One may oversleep, and then slow down the routine; skip a day (possibly due to external circumstances), and then start skipping more; skip a few months, and then stop exercising for years, saddened by breaking a streak or observing setbacks. Perhaps it is helpful to keep in mind that those do happen, and that it is still beneficial to keep going after that.
Upon catching a cold, apparently it is generally okay to exercise when sick, unless you have a fever, or perhaps other symptoms below the neck (coughing, body aches, etc).
Generally a bad mood harms motivation, makes it harder to do things like regular exercises. On those days it seems useful to remember that exercises help to combat it. Perhaps the same applies to working on hobby projects, reading, studying, and so on: hard to start when you are in a bad mood, but then they help to shake it off or to temporarily forget about the things bothering you. Likewise with physical exercises and cold.
For a timer, a wall clock may work, though it is less convenient
to check while facing the floor; a sound-based timer is
better. For Android devices, Just Another Workout Timer is
pretty good (available from F-Droid; if the screen is not kept
awake, one may have to enable ticks to keep Android from putting
JAWT to sleep: see JAWT issue #18). Then there are workout music
mixes with timers on YouTube. Surprisingly, I have not found a
suitable timer for regular GNU/Linux systems, but they can be
set easily with a shell script and a TTS system (such
as Festival; the festival package in Debian), for
instance:
#!/bin/sh -e
say() {
echo "$2"
echo "$2" | festival --tts &
sleep "$1"
}
# Announce an exercise 8 seconds in advance, then count down, announce
# it again, wait for its duration minus 8 seconds (leaving those for
# the next announcement). Using 8 instead of 10, so that 10 seconds
# can be the safe minimum time for an exercise (or a rest).
announce() {
say 5 "Next: $2"
say 1 "3"
say 1 "2"
say 1 "1"
say $(($1 - 8)) "$2"
}
case $1 in
cardio)
# https://www.youtube.com/watch?v=7HuB5lHlhpA
say 2 "Cardio workout"
# 4 repetitions here.
for i in $(seq 4); do
announce 30 "butt kicks"
announce 15 "rest"
announce 30 "in and out squat"
announce 15 "rest"
announce 30 "jumping jacks"
announce 15 "rest"
announce 30 "mountain climbers"
announce 15 "rest"
announce 30 "plank shoulder/knee tap"
announce 15 "rest"
announce 30 "step toe tap"
announce 15 "rest"
announce 30 "fast feet"
if [ "$i" -lt 4 ]; then
announce 90 "break number $i"
fi
done
;;
stretch)
# https://www.youtube.com/watch?v=FI51zRzgIe4
say 2 "General stretching"
announce 30 "lumbar rotation (right)"
announce 30 "lumbar rotation (left)"
announce 30 "hamstring stretch (right)"
announce 30 "hamstring stretch (left)"
announce 30 "piriformis stretch (right)"
announce 30 "piriformis stretch (left)"
announce 30 "kneeling hip flexor stretch (right)"
announce 30 "kneeling hamstring stretch (left)"
announce 30 "kneeling hip flexor stretch (left)"
announce 30 "kneeling hamstring stretch (right)"
announce 30 "seated spinal twist (right)"
announce 30 "seated spinal twist (left)"
announce 30 "child's pose"
announce 30 "upper back extension"
announce 30 "upper trapezius stretch (left)"
announce 30 "upper trapezius stretch (right)"
;;
back)
# https://www.youtube.com/watch?v=BPlCatqZRPI
say 2 "Back stretching"
announce 40 "mindful shoulder circles"
announce 40 "angel wings"
announce 40 "cat cow"
announce 40 "thoracic rotation (right)"
announce 40 "thoracic rotation (left)"
announce 40 "extended puppy pose"
announce 40 "sphinx"
announce 40 "locust pose"
announce 40 "shoulder stretch (right)"
announce 40 "shoulder stretch (left)"
announce 20 "neck stretch (right)"
announce 20 "neck stretch (left)"
announce 20 "neck stretch (forward)"
announce 40 "heart opener"
announce 10 "easy twist"
announce 40 "dynamic camel"
announce 15 "leg shake"
announce 40 "shoulder bridge"
announce 40 "deep relaxation"
;;
*)
say 2 "Unknown workout name"
exit
;;
esac
# Wait for 8 seconds, matching the shift introduced for announcements
# (so that the last exercise is not cut by 8 seconds).
sleep 8
say 0 "workout complete"
To pause, one can stop the job with C-z. and then resume
with fg 1.
Exercises like pull-ups are often done in sets, with rests between them. The Guide to Sets, Reps, and Rest Time in Strength Training suggests rests of 30 to 60 seconds for muscle hypertrophy and endurance, 2 to 5 minutes for strength.
It is commonly suggested to have rest days once in 7 to 10 days: e.g., "Why You Need Rest and Recovery After Exercise". I felt fine not having any rest days at all, but the rest days do seem useful: both for exercising efficiency (proper muscle recovery) and for planning: sometimes there are chores that compete with exercising for the schedule, but designating days spent on such chores as rest days helps to resolve it.