Commentary: Are Children Like Werewolves? Full Moon and Its Association with Sleep and Activity Behaviors in an International Sample of Children

The article, " Are Children Like Werewolves? Full Moon and Its Association with Sleep and Activity Behaviors in an International Sample of Children " by Chaput et al. (1) was quite fascinating and thought-provoking. However, there is a potential flaw in their research – and perhaps in all the medical literature on this subject. Curiously, the study found a small but measurable difference in sleep duration in children as a function of the lunar cycle. Specifically, they found that nocturnal sleep duration is ~5 min shorter around full Moon compared to new Moon in their sample of children selected from around the world. One might reasonably speculate that this could be due to a brighter night sky during the full moon. To further evaluate this possibility, I would agree with the authors when they say, " Future experimental work is needed to determine if the human biology is in any way synchronized with the lunar cycle. " And that " Future research should also examine if the full moon may have a larger influence on subgroups of vulnerable children, e.g., those with mental disorders or physical ailments. " However, I believe that it is important that any future research stratify the full Moons by relative proximity to Earth. Our Moon does not orbit Earth in a perfect circle but rather in an ellipse. Thus, during every lunar orbit, there is a point in the ellipse when the Moon is closest to Earth (perigee) and a point when it is farthest from Earth (apogee). On average, the Moon is about 238,800 miles (384,300 km) from Earth. However, due to the elliptical shape of the lunar orbit, the absolute distance varies between 225,804 miles (363,396 km) at perigee and 251,968 miles (405,503 km) at apogee. Our Moon cycles through perigee and apogee approximately once each month but these points do not necessarily correlate with the lunar phases (new Moon, half Moon, full Moon, etc.). There are times, however, when the two cycles are synchronized and a full Moon would coincide with perigee or apogee. The Moon's gravitational pull on earth is strongest during perigee. The gravitational force exerted by the Moon on Earth, as calculated by Newton's Law, is quite small. Nevertheless, the combined effects of the Moon and Sun do have a noticeable influence on our tides and twice per month we have alignment of the Sun, Earth, and Moon (i.e., …