Just today I read about New Year's promises and how they often seem to be forgotten in a month or two. But as the article said, even a short period is better than no improvement in your habits at all.
The article also said that it takes about nine (9) months for a new healthy habit to stick to the point where not doing it makes you feel worse than doing it!
For the record I feel guilty and don't really wake up if I skip my morning excercise. Every morning except Sundays ("He rested on the seventh day...") I do a routine of about 15 minutes with the window open to ventilate the bedroom. Sit-ups, push-ups, pull-ups, squats, bows... On the mornings I'm going to take a shower I do more repeats in a fast tempo to really sweat. The rest of the days I do it to the tempo of Yoga breathing: Inhale through the nose for 3 seconds, outhale for 7 seconds while keeping the strained position. That'll make six repeats in a minute, two minutes for each posture is plenty enough. Compared to going to a gym my way has plenty of advantages: First, you don't have to go anywhere so you'll save the traveling time. Second, you don't have to worry about fashion, you can do it all in Adam's suit. Third, no fossil fuel is used which saves both your money and the environment. Fourth, you don't have to worry about what other people think about you as you're alone. Fifth, as you're training by yourself you don't have to explain anybody why you weren't there yesterday (having a hangover after a Scotch tasting night...) Etc.
