PLoS ONE, confirms what beer drinkers have known for years: drinking beer can help you sleep. In the July 2012 edition, female nurses were given non-alcoholic beer to determine if it helped them sleep better. In case you were wondering, the beer was San Miguel 0.0%. One group of nurses were given a bottle to drink in the evening after a stressful shift, while another group got nothing. After only two weeks, the nurses who drank the near-beer experienced a better quality of sleep than the other group. The total length of sleep did not change. However, sleep latency (the time needed to fall asleep) was reduced in the beer group.
This improved sleep had other measurable benefits. Improved sleep also reduced the level of anxiety experienced by nurses in the beer group compared to their abstaining counterparts. The reasons for this improved sleep was not clear. However, it is known that hops can increase the activity of the brain chemical GABA (Gamma-AminoButyric Acid). GABA tends to have a sedative effect in people. Another suggestion is that a chemical in hops (2-methyl-3-buten-ol) can act like a narcotic. Hops might also affect serotonin and help melatonin work. Both of these brain chemicals help people sleep.
The researchers suggested that increasing the hop content could lead to a greater sedative action. I don't think San Miguel is the hoppiest beer out there. Sadly, drinking a double IPA might not help you count more sheep. This exponentially greater hop intake is also paired with more alcohol. Alcohol can sometimes interfere with a good nights rest.