I'm going to keep this short and sweet.
For all of you out there that go to the gym to either lift or do cardio and want to burn more without necessarily adding more weight.
The so called "Afterburn" which is the effect of calorie burning after exercise is complete. So basically its the freebie calories lost after I just busted my ass in the gym.
So how long does this last?
Some studies say it only lasts for 35 minutes while others say 24 hours.
Why such a big difference?
Difference is in intensity, length of time, mode of exercise ( cardio vs resistance training vs circuit training)
I didn't want to go into all the science behind it so I boiled it down to if the body needs more oxygen during exercise, it will also need more during recovery as well.
This is to help the cells restore themselves back to pre-exercise levels.
Cardio Training
One study 2014 (Mann et al.) : the greater the intensity of the exercise the higher the afterburn.....thanks genius!
Second study 2011 (Knab et al.): burned 37% (190 kcal) more calories in 14 hours of rest post 45 minute cycling (519 kcal)
This means a 20 minute sprint as fast as possible for around 30 seconds done 10 times with a 90 second rest period per round will give you a larger afterburn than just running moderately for 30 minutes at a steady pace.
Doing the same cardio session over and over again won't shock your body enough to give it reason to burn more.
Resistance Training
Traditional vs High Intensity resistance training (HIRT)
One study 2012 (Paoli et al.):
Traditional (4 sets, 8-12 reps, 70%-75% of 1 rep max):
burned 5% (99 kcal) greater than rest.
HIRT (3 sets,6 reps max - 20 sec rest - same weight to failure (2-3 reps) - 20 sec rest (1-2 reps) - 2.5 min rest)
burned 23% (452 kcal) greater than rest.
Bottom line
If you want a greater afterburn do higher intensity cardio or higher intensity resistance training.
The effects can last over 24 hours!