HIIT should be in every guy's regimen.

Studies have shown that performing high-intensity interval training, during which you alternate an intense burst of activity with a less intense active resting period, can help lower insulin resistance, improve overall fitness, and maybe even lead to a longer life.

And now new research from the University of Turku is suggesting HIIT floods your brain with feel-good endorphins, which might alleviate the physical pain and mental struggle involved with the somewhat agonizing workouts. But it's a bit of a catch-22.

In the study, published in the journal Neuropsychopharmacology, researchers put 22 adult males through a 60-minute, moderate-intensity aerobic exercise session or a HIIT routine, then monitored their mood during and after. Participants were also injected with a radioactive substance that binds to the specific receptors linked to endorphins—to visually track their activation.

So, while HIIT can get your positive juices that manage pain and emotions flowing, it also spurred people to have negative feelings mid-workout (20 more burpees?!), which was then linked to another push of endorphins, thought to cancel out the bad vibes.

Performing one hour of steady-state cardio didn’t produce the same release of opioid-like compounds. However, it did elevate mood in the participants (think: runner's high), which researchers believe could be key in getting people to exercise on a more consistent basis, since super-difficult workouts can be discouraging for those new to working out.

Bottom line: HIIT still has a huge amount of benefits, and is incredibly helpful for weight loss, but you want to find the type of exercise that keeps you coming back for more when you're getting into a new regimen. Consistency is key.