If time to do exercise is an issue over the festive season have a go at this 15 minute high intensity session. It requires no equipment. Just you, and 16 minutes of motivation. Maybe have a strong tea/coffee 45 minutes before you plan to do it. Google any exercise you are not sure of.
30s per exercise, 30s break X 3 rounds. do not stop
1- Run on the stop as fast as possible
2- Alternating reverse lunges (hold a small child, pet or spouse for extra resistance!).
3- Mountain runners
4- Press ups
Or have a go at this 10 minute workout
30s sprint on the spot, 30s break x 10