Quite a few studies have been done on what is called “Interval Training” or Interval Exercise. Done 3 times a week for about 12 minutes each time produces better results than hours at the gym doing longer workouts. For quick and easy exercise, interval training may be your best bet.
In essence interval training is where you do several short burst of very intense exercise with short recovery period of low intensity in between. There are many variations of this but most of them involve a short warm up, then about 1 to 2 minutes of intensity then 1-2 minutes of recovery, back and forth several times. I have found it easiest to do this on a treadmill, but you can do it running in place at home or even doing jumping jacks. I warm up with a fast walk for a few minutes. I then do 1 1/2 minutes of running – fast enough running to get my heart rate up to about 160 or 165, then back to fast walking for 1 1/2 minutes. I do this 4 times. The entire routine is done in 12 to 15 minutes. I do it every other day in addition to my daily Canadian Air Force Exercises which I do daily in under 10 minutes. More about CAF exercises in other posts. Both High intensity interval training (commonly referred to as HIIT) and CAF exercises are quick and easy exercise routines that you can do anywhere.
Here are a couple links about Interval Training that I found helpful:
https://www.shape.com/fitness/workouts/interval-training-short-workouts-really-pay
https://www.mayoclinic.org/healthy-living/fitness/in-depth/interval-training/art-20044588
I LOVE the Canadian Air Force routine! I love the fact it only takes 12 minutes plus you don’t need any equipment. I’ve been using a rebounder (trampoline) for the jogging and hopping step as that as added health benefits too.
A researcher you may enjoy is Dr. Joan Vernikos. She is a NASA scientist and did research on astronauts, including John Glenn, studying the effects of weightlessness in space and aging. Her results are fascinating. She found that sitting at a day job or other sedentary activities can have the same affect on a body as weightlessness in terms of aging and other medical conditions. Her book is “Eating Kills, Moving Heals”. She recommends NEAT activities – non exercise activity thermogenesis.