I’ve been a part of so many confusing conversations that go: if alcohol is a depressant, why do we drink it to party? Good question. If alcohol is meant to sedate you, why does it give you the energy to run, jump, dance, laugh, make-out, climb, and wrestle for hours on end? And if alcohol is such a downer, why does much of the world rely on it for fun upper times?

It turns out that alcohol has both sedative and stimulating effects. Past research has found that what you feel when operates on a bit of a bell curve. You mainly feel the stimulant effects on the ‘ascending limb’ of the blood alcohol curve – as you’re getting pissed – and the sedative effects primarily on the ‘descending limb’ – as you’re sobering up. The fact that you feel different effects from alcohol on either side of the blood alcohol curve is called a ‘biphasic’ response, and it explains the why you turn from a happy, energetic, bouncing bean in the bar into a slump-shouldered sad character as you shuffle into the cab line.

Earleywine tested this in 1993 in a study that took one hundred eighty-seven undergraduate students and got them to do what they do every weekend: get a bit pissed. They either drank 2 drinks in an hour or 4 drinks in an hour, then were asked to rate how they felt on the ‘stimulant subscale’ and the ‘sedative subscale’. The participants filled out this survey at: (1) immediately after consuming two drinks in 1 hr, (2) 1 hr after finishing two drinks in 1 hr, (3) immediately after consuming four drinks in I hr, and (4) 1.5 hr after consuming four drinks in 1 hr.To measure stimulation, they used the terms elated, energized, excited, stimulated, talkative, up, and vigorous. And for sedation, it was difficulty concentrating, down, heavy head, inactive, sedated, slow thoughts, and sluggish.

The results were pretty much as predicted. Stimulant effects were much higher when climbing up the Blood Alcohol ladder than when descending it in both the 2 drink and 4 drink test groups. However, the results looking at sedative effects were less straightforward; in the high dose – 4 drink – test group, there were reports of the sedative effects kicking in on the descending, sobering-up limb of the curve. But this wasn’t seen in the low dose – 2 drink – group, which didn’t really report strong feelings in either direction as they slid back down the curve.

Looking at the stimulating and sedating effects of booze, it looks like its a simple case of what goes up must come down. You’re stimulated for a bit, then sedated, but that’s all good – getting tired is a sign that you should get an early morning kebab then head to bed. But be aware – the higher you fly up your Blood Alcohol Concentration curve, the further you’ve got to fall. Which explains these people.