By Marc Sorenson, EdD, Sunlight Institute
Almost no one realizes the dramatic improvement that sun exposure can make on athletic performance. I helped Dr. John Cannell obtain translations of many esoteric and decades-old studies that had been forgotten, probably due to the fact that sun lamps were used to create some of the improvements in athletics, and have fallen out of favor due to the sunscare movement. I co-authored a paper with Cannell, called Athletic Performance and Vitamin D. That paper is the source of much of the material covered here, and it demonstrates the remarkable, positive effect of sun or other ultraviolet (UV) exposure on human performance. I would also strongly suggest that the readers avail themselves of Dr. Cannell’s book on the subject, called The Athlete’s Edge, which discusses in far greater detail the materials introduced here.
One of the salient studies on UV exposure took place in 1957 and assessed the influence of sun exposure on strength and performance over a two-year period. During that time six subjects were able to increase athletic performance and muscle trainability through systematic UV exposure. But when vitamin D3 was used, it not only did not work, it inhibited the performance-enhancing effect of the UV. I sometimes fear the public is beginning to believe that if sun exposure is proven to enhance human health, one needs only to take a vitamin D pill. Don’t get pulled into that idea. Sun exposure will always be more important than any of the photoproducts whose production it stimulates.
Here are some of the other salient studies on sun exposure and performance. In 1938, Russian researchers demonstrated that a series of four UV treatments improved speed in the 100-meter dash compared to four non-irradiated students, when both groups were undergoing daily physical training. The times improved from 13.51 seconds to 13.28 seconds in the non-irradiated group and from 13.63 to 12.62 seconds in the irradiated group. In other words, the UV-treated group improved by three-fourths of a second more than the non-UV group. That may seem like a relatively small improvement, but three-fourths of a second better time in a 100-meter dash could be the difference between first and last place!
German research from 1944 showed that the exposure of 32 medical students to UV, twice weekly during for six weeks, associated with a 13% improvement in endurance, whereas performance of a control group was unchanged.
Other German research shows that the ability of a muscle to gain strength (trainability) is much better in summer than winter, and peaks in September. In fact the trainability was 2½ higher that the average monthly trainability for the entire year.
When we consider reaction time, muscle and bone strength, speed and endurance, we should realize that these measurements are not only important for athletes; they are important for all aspects of living for all people. Everyone wants to be stronger, quicker, and faster, as well as have more endurance in daily activities. So embrace the sun, but do it safely and do not burn.
 Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ. Athletic performance and vitamin D. Med Sci Sports Exerc. 2009 May;41(5):1102-10.
 E. Seidl and Th. Hettinger. The Effect of Vitamin D3 on the Strength and Performance of a Healthy Adult. International Journal Physiology, including Industrial Physiology, Vol. 16, Pages 365-372 (1957).
 Gorkin Z, Gorkin MJ, Teslenko NE. [The effect of ultraviolet irradiation upon training for 100m sprint.] Fiziol Zh USSR. 1938;25:695-701.
 Lehmann G, Mueller EA. [Ultraviolet irradiation and altitude fitness.] Luftfahrtmedizin. 1944;9:37-43. [Article in German].
 Hettinger T, Muller EA. Seasonal course of trainability of musculature. Int Z Angew Physiol. 1956;16(2):90-4.
 Sigmund, R. The effect of ultra-violet rays on the human reaction time. Strahlentherapie.1956;101(4):623-9.
 Seidl E. [The effect of ultraviolet irradiation on reaction time.] Int Z Angew Physiol. 1958;17(4):333-40.
By Marc Sorenson, EdD, Sunlight Institute
After coming across some research having to do with sun exposure and the seasonality of fractures, I thought it wise to share it with my readers.
In high latitude areas, which have far less sun availability than lower latitude areas, we would expect rates of hip fracture to be high, and such is the case. Sweden is a country that has large differences in latitude, and in research performed there it was shown that the higher the latitude and the lesser the sun exposure, the greater was the risk of hip fracture. In other words, significantly more hip fractures occurred in the northern part of the country compared to the middle and southern parts. Another Swedish investigation demonstrated that in men, hip fracture risk was 37.5% lower in summer than winter. Women had a 23.5% reduced risk in summer.
Research from Norway showed similar results. Hip fracture risk in men was 40% higher in winter than summer, and in women the risk was 25% higher.These fluctuations in seasonal hip fractures indicate a loss of bone mass during periods of low sun exposure (winter) and an increase in bone mass during periods of high sun exposure (summer). In other words, sun exposure is able to reverse bone loss, or osteoporosis. Other studies show similar patterns of bone strength based on sun exposure or lack thereof.
The importance of sunlight in maintaining and producing strong bones has been known since antiquity. Dr. Richard Hobday, author of The Healing Sun, writes the following comments and a history in an online article. “Traditionally, sunlight deprivation has been linked with weak or brittle bones. One of the earliest references to this was made more than two thousand years ago by the Greek historian Herodotus (480-425 BC), who noted a marked difference between the remains of the Egyptian and Persian casualties at the site of battle of Pelusium which took place in 525 BC:
‘At the place where this battle was fought I saw a very odd thing, which the natives had told me about. The bones still lay there, those of the Persian dead separate from those of the Egyptian, just as they were originally divided, and I noticed that the skulls of the Persians were so thin that the merest touch with a pebble will pierce them, but those of the Egyptians, on the other hand, are so tough that it is hardly possible to break them with a blow from a stone. I was told, very credibly, that the reason was that the Egyptians shave their heads from childhood, so that the bone of the skull is indurated by the action of the sun — this is why they hardly ever go bald, baldness being rarer in Egypt than anywhere else. This, then, explains the thickness of their skulls; and the thinness of the Persian’s skulls rests upon a similar principle: namely that they have always worn felt skull-caps, to guard their heads from the sun.’ Herodotus, ‘The Histories’”
The message is this: Don’t hide yourself from the sun; rather, embrace it in a safe manner, and that will protect your bones.
 Nilson F, Moniruzzaman S, Andersson R. A comparison of hip fracture incidence rates among elderly in Sweden by latitude and sun exposure. Scand J Public Health. 2014 Mar;42(2):201-6.
 Odén A, Kanis JA, McCloskey EV, Johansson H. The effect of latitude on the risk and seasonal variation in hip fracture in Sweden. J Bone Miner Res. 2014 Oct;29(10):2217-23.
 Solbakken SM1, Magnus JH, Meyer HE, Emaus N, Tell GS, Holvik K, Grimnes G, Forsmo S, Schei B, Søgaard AJ, Omsland TK.
 Grønskag AB1, Forsmo S, Romundstad P, Langhammer A, Schei B. Incidence and seasonal variation in hip fracture incidence among elderly women in Norway. The HUNT Study. Bone. 2010 May;46(5):1294-8.
 Richard Hobday. The Healing sun: Sunlight, Brittle Bones, and Osteoporosis. http://sunlightenment.com/the-healing-sun-sunlight-brittle-bones-and-osteoporosis/. (accessed February 5, 2016)
By Marc Sorenson, EdD, Sunlight Institute…
We all know that high sunlight exposure in adults leads to higher vitamin D levels. However, a most interesting piece of research also shows that your birth month has a considerable influence on vitamin D levels. In an Italian study, it was found that those who were born in winter, rather than spring and summer, were 11% more likely to develop vitamin D deficiency later in life.[i] This is an important finding, since many diseases are related in one way or another to season of birth. For example, a greater risk of obesity risk is observed in Canadians born in winter. Nevertheless, other factors such as inactivity are more important than season of birth.[ii]
This is another study that ties sunlight to vitamin D. But the question may still be asked: Is the relationship of birth seasonality to disease due to vitamin D or sunlight, or both? Whatever the answer, sunlight is the factor that makes vitamin D, so safely soak up the sun whenever you have the opportunity, and when it is too cold or overcast, safely use a sun lamp or tanning bed.
[i] Lippi G, Bonelli P, Buonocore R, Aloe R. Birth season and vitamin D concentration in adulthood. Ann Transl Med. 2015 Sep;3(16):231.
[ii] Wattie N1, Ardern CI, Baker J. Season of birth and prevalence of overweight and obesity in Canada. Early Hum Dev. 2008 Aug;84(8):539-47.
By Marc Sorenson, EdD, Sunlight Institute
Serotonin is one of the most potent natural mood enhancers produced in the body. As previously mentioned in one of my blogs, men whose levels of serotonin were measured on a very bright day produced eight times more serotonin than those who were measured on a cloudy, dismal day. Serotonin levels were also seven times higher in summer than winter. Serotonin works in concert with melatonin; serotonin keeps keeps us bright and happy during the sunny day and melatonin lets lets us sleep during the dark night. Unfortunately, lack of sunlight in winter may also lead to too much daytime melatonin production, which may lead to aggressive behavior.
A 2015 report from Proceedings of the Royal Academy B, demonstrated that female rats who had the least sunlight exposure per day displayed the most aggression. A similar increase in aggression was not observed in male rats.
An increase in melatonin was given as the reason for the aggression, since when winter approaches, sunlight decreases and melatonin increases. (Of course, serotonin also decreases, as stated in the aforementioned research.) Melatonin increases aggression, according to this study, by acting on the adrenal glands, causing a release of a hormone called DHEA, which has been consistently been linked to aggression in both mammals and birds.
I’m not entirely convinced that that aggression was not caused more by the drop in serotonin than the increase in melatonin. Either way, you boyfriends and husbands should be sure that your lady love gets plenty of sunlight or other form of UV light every day of the year, or you may be in trouble!
 Lambert GW, Reid C, Kaye DM, Jennings GL, Esler MD. Effect of sunlight and season on serotonin turnover in the brain. Lancet. 2002 Dec 7;360(9348):1840-2.
 Proceedings of the Royal Academy B 2015. Reported by Carly St. James, Empire State News. http://www.empirestatenews.net/2015/11/19/a-spike-in-female-aggression-can-be-linked-to-this-seasonal-change/ [accessed November 19, 2015]}