Peak performance isn’t just for elite athletes. While Vitamin D may make a difference in performance for those competing at the highest levels, it can also make a difference for the rest of us seeking to improve or maintain physical performance in our daily lives.
According to a recent New York Times article:
Last year, a 15-member team of nutrition experts noted in The American Journal of Clinical Nutrition that “randomized trials using the currently recommended intakes of 400 I.U. vitamin D a day have shown no appreciable reduction in fracture risk.”
“In contrast,” the experts continued, “trials using 700 to 800 I.U. found less fracture incidence, with and without supplemental calcium. This change may result from both improved bone health and reduction in falls due to greater muscle strength.”
A Swiss study of women in their 80s found greater leg strength and half as many falls among those who took 800 I.U. of vitamin D a day for three months along with 1,200 milligrams of calcium, compared with women who took just calcium. Greater strength and better balance have been found in older people with high blood levels of vitamin D.
Dr. John Cannell of the Vitamin D Council notes in his newsletter, Why Athletic Performance Matters, that:
Many people don't realize how fatal falls can be in the elderly. In 2003, the CDC reported that 13,700 persons over 65 died from falls in the USA, with 1.8 million ending up in emergency rooms for treatment of nonfatal injuries from falls. Falls cause the majority of hip fractures which, if they don't result in death, often result in admission to a nursing home. That's 13,700 deaths, hundreds of thousands of surgeries, countless nursing home admissions, and tens of billions in health care costs every year—all from impaired athletic performance. That's why it matters.
A Reuters report on how Vitamin D affects physical function in elderly, finds that "Older men and women who fail to get enough vitamin D -- either from their diets or exposure to the sun -- are at heightened risk for muscle weakness and poor physical performance, a study shows. This is troubling, researchers say, given the high numbers of older folks who are deficient in vitamin D." According to research done by Dr. Denise K. Houston at the Wake Forest University of Medicine: "...physical performance and grip strength were 5 to 10 percent lower in people with low blood levels of vitamin D levels, compared with those with normal levels."
However simply getting more exposure to the sun may not be enough without other lifestyle changes. Being overweight can reduce Vitamin D levels in the blood according to this Science Daily report:
It's not yet clear why overweight elderly adults have low levels of vitamin D in their blood. However, researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University (USDA HNRCA) have found that lack of sun exposure may not account for low levels of vitamin D in elders who are overweight. ... "The most likely explanation seems to be that vitamin D is sequestered in fat tissue, reducing its entry into the blood."
Sunday, February 24, 2008
Sunday, February 17, 2008
Sunshine and PGA Tour Wins
No slight to Arnie and Jack, but the southern states have produced more PGA Tour winners since 1960 than the northern states. There are probably numerous reasons for this including more time to practice and play in warmer southern climates. Most top PGA Tour pros live in southern states and play the same courses during a season. However they differ in where they were born and it appears that those born in the south have a better chance for success as a PGA Tour Pro.
Being outdoors frequently provides exposure to sunlight which produces Vitamin D, a potent steroid hormone. This may also be a factor in the south's advantage in golf. The correlation between population adjusted number of top pro golfers and the UV Index in their birth states is similar to what we found for top (Division 1A) college football players (see Football’s Southern Exposure). However in terms of sheer numbers, top pro golfers are relatively few and far between averaging roughly 1 or 2 pros per 10 million in population.
Using the Wikipedia data, we determined the birth state of the (American born) PGA Tour Pro(s) with the most wins in each season since 1960. There were 38 unique winners (with ties) and each golfer was counted only once if they were multiple year winners. The golfers were each placed into one of seven groups by yearly average UV Index range in their birth state (<5.25; 5.25-5.74; 5.75-6.24; 6.25-6.74; 6.75-7.24; 7.25-7.74; and >=7.75). The total number of golfers in each group was divided by the total population of all states in each group.
Figure 1 illustrates the correlation (R-squared = .56) between the number of US golfers per 10 million population their birth state average UV Index. Big states such as Texas, California and Florida were divided into separate regions since the UV Index varied significantly within the state. For example the UVI in Southern California (LAX) is 7.61versus 6.31 in the San Francisco area. Population was equally divided in each region of the state. The tilt in the linear fit toward the high UV Index states is statistically significant (p = .04).
Figure 1. High UV Index States Produce Significantly More Top PGA Tour Winners.
Correlation is no proof of cause and it's impossible to tell how much of a factor (if any) sunshine and Vitamin D are in shaping a young golfer's chances of future success. Even those in the south face long odds of being a top PGA Tour pro. However, most of us would be happy enough with shaving a few strokes off our handicaps. Even with this modest goal there's no way to be sure if lessons, new equipment or other tips are making a difference. However there seems to be little downside in supplementing one's diet with more Vitamin D in the north, particularly in the winter months when the UV Index can be very low.
Table 1. PGA Tour Pros With Most Yearly Wins Since 1960.
Being outdoors frequently provides exposure to sunlight which produces Vitamin D, a potent steroid hormone. This may also be a factor in the south's advantage in golf. The correlation between population adjusted number of top pro golfers and the UV Index in their birth states is similar to what we found for top (Division 1A) college football players (see Football’s Southern Exposure). However in terms of sheer numbers, top pro golfers are relatively few and far between averaging roughly 1 or 2 pros per 10 million in population.
Using the Wikipedia data, we determined the birth state of the (American born) PGA Tour Pro(s) with the most wins in each season since 1960. There were 38 unique winners (with ties) and each golfer was counted only once if they were multiple year winners. The golfers were each placed into one of seven groups by yearly average UV Index range in their birth state (<5.25; 5.25-5.74; 5.75-6.24; 6.25-6.74; 6.75-7.24; 7.25-7.74; and >=7.75). The total number of golfers in each group was divided by the total population of all states in each group.
Figure 1 illustrates the correlation (R-squared = .56) between the number of US golfers per 10 million population their birth state average UV Index. Big states such as Texas, California and Florida were divided into separate regions since the UV Index varied significantly within the state. For example the UVI in Southern California (LAX) is 7.61versus 6.31 in the San Francisco area. Population was equally divided in each region of the state. The tilt in the linear fit toward the high UV Index states is statistically significant (p = .04).
Figure 1. High UV Index States Produce Significantly More Top PGA Tour Winners.
Correlation is no proof of cause and it's impossible to tell how much of a factor (if any) sunshine and Vitamin D are in shaping a young golfer's chances of future success. Even those in the south face long odds of being a top PGA Tour pro. However, most of us would be happy enough with shaving a few strokes off our handicaps. Even with this modest goal there's no way to be sure if lessons, new equipment or other tips are making a difference. However there seems to be little downside in supplementing one's diet with more Vitamin D in the north, particularly in the winter months when the UV Index can be very low.
| UV Index | Birth State | PGA Tour Pro |
|---|---|---|
| 10.00 | Hawaii | |
| 9.37 | Florida (MIA) | |
| 8.69 | Florida (TPA) | |
| 8.39 | Texas (DFW) | Brooks, Magee, Kite, Travino |
| 8.36 | Louisiana | Sutton |
| 8.15 | Alabama | Green |
| 8.02 | Florida (JAX) | Duval, McCumber |
| 7.95 | Texas (HOU) | Rogers, Crenshaw |
| 7.90 | New Mexico | Jones |
| 7.75 | Mississippi | |
| 7.75 | Arizona | |
| 7.61 | California (LAX) | Woods, Mickleson, Pavin, Stadler, Casper |
| 7.44 | South Carolina | |
| 7.37 | Georgia | |
| 7.06 | Arkansas | |
| 7.00 | Nevada | |
| 6.97 | Tennessee | |
| 6.88 | Oklahoma | Tway, Morgan |
| 6.70 | North Carolina | Love III, Floyd |
| 6.48 | Colorado | |
| 6.41 | Virginia | Strange, Wadkins |
| 6.40 | Kansas | |
| 6.40 | Utah | |
| 6.31 | California (SFO) | Miller, Lema |
| 6.17 | Kentucky | |
| 6.11 | Missouri | |
| 6.08 | West Virginia | |
| 5.88 | Maryland | |
| 5.87 | Delaware | |
| 5.83 | Indiana | Zoeller |
| 5.79 | New Jersey | Colbert |
| 5.67 | Pennsylvania | Palmer |
| 5.63 | Idaho | |
| 5.59 | Nebraska | |
| 5.53 | Iowa | Purzer |
| 5.52 | New York (JFK) | |
| 5.34 | Ohio | Cook, Watson, Nicklaus |
| 5.31 | Illinois | |
| 5.29 | Connecticut | |
| 5.25 | Rhode Island | Andrade |
| 5.16 | Michigan | Peete, Hill |
| 5.12 | South Dakota | |
| 5.11 | Wisconsin | |
| 5.10 | Massachusetts | Azinger |
| 5.01 | New York (BUF) | Levi |
| 5.00 | New Hampshire | |
| 4.97 | Wyoming | |
| 4.97 | Montana | |
| 4.85 | Oregon | |
| 4.84 | Maine | |
| 4.80 | Minnesota | Jansen |
| 4.76 | Vermont | |
| 4.59 | North Dakota | |
| 4.41 | Washington | Couples |
| 2.22 | Alaska |
Saturday, February 2, 2008
New England Patriots’ Midwinter Blues
In spite of putting together a perfect regular season, the Patriots' performance has often been questioned as their margin of victory declined. Was this just coincidental or is there a systematic trend at work that makes it difficult to maintain peak performance throughout the course of a complete football season? Dr. Michael Holik has stated that Human skin exposed to sunlight on cloudless days in Boston (42.2 degrees N) from November through February produced no previtamin D3. Could an insufficiency of Vitamin D be the cause of the Patriot's drop off from peak performance?
The pro football season starts in late summer and ends in the dead of winter, spanning a wide variation in solar intensity as measured by the Ultra Violet (UV) Index. An earlier post, Sunshine and Super Bowl XLII, noted southern teams have a bit of an edge for multiple Super Bowl wins. New York and New England are both northeastern teams and both have comparable declines in solar exposure as the season wears on. Is there a drop off in performance, as sunshine gets too weak to produce Vitamin D? More specifically, has there been any difference between the Patriots’ and Giants’ performance relative to the UV Index (UVI) over the course of the season?
The New England Patriots played their pre-season games at Tampa (UVI estimate = 11.7); versus Tennessee (7.5); at Carolina (8.8); and versus the New York Giants (6.9). The Pats started the regular season at the New York Jets (5.0) with a five-week moving average UVI of about 8.0. As the schedule unfolded in the fall, the UVI average steadily declined to 5.0 at the end of September; 4.5 at the end of October; 2.0 at the end of November; 1.5 at the end of December. Home field advantage kept the Patriots home in January and didn’t help with sun exposure.
Figure 1 summarizes the New England Patriots’ points scored, points allowed and total points over the course of the season as a function of the estimated 5 week moving average of the UV Index. A linear fit of the data is also shown to illustrate trends, though correlations are small since scores in any football game have a big standard deviation of approximately 14 points around the line. The trend lines show that the offense scored fewer points on average as the UVI declined, while the defense gave up more points. The Patriots had started the season blowing out opponents and beating the spread by a wide margin. While they ended the season unbeaten, the games were often much closer and results often fell short of Vegas’ expectations.
The New York Giants UVI also started high (7.8) and declined as expected during the fall into winter. However, the Giants had two playoff games in January that took them to Tampa Bay and Dallas where the solar intensity was much greater than what the Patriots experienced at home. The Giants’ offensive production trend (shown in Figure 2) decreased slightly as the UV Index declined. On defense the trend actually improved a bit (allowed fewer points) as a function of decreasing UVI.
Figure 2. Giants’ Offense Has Declined Slightly as UVI Declined.
With the Patriots’ 5 week moving average UVI currently at 2.0 they should win 32.4 - 18.0 over an average opponent. In contrast, the Patriots’ overall season average score was 35.6 - 17.0, Therefore based on UVI the Pats should under perform by 3.2 points on offense and 1.0 points on defense or a total of 4.2 points. As a result of the playoff games in the south, the Giants’ 5 week moving average UVI is currently 2.9. The linear fit in Figure 2 suggests they should beat an average opponent by 22.8 – 20.7. In contrast, the Giants’ overall season average score was 23.2 – 21.2. The Giants would be expected to under perform on offense by 0.4 points but make it up on defense. UVI exposure would appear to favor the Giants by nearly 4 points… not enough to offset the 12.5 point line for the game, but enough perhaps to make the game interesting.
While there isn't enough data here to draw any firm conclusions, the noticeable drop in the Pats' offensive production with declining UV Index levels suggests that Vitamin D levels could be a factor. Further research may shed light on this question but until then, Vitamin D should be monitored and supplements may be beneficial for maintaining peak performance.
Table 1. Sun Exposure Declines Substantially During the Football Season
The pro football season starts in late summer and ends in the dead of winter, spanning a wide variation in solar intensity as measured by the Ultra Violet (UV) Index. An earlier post, Sunshine and Super Bowl XLII, noted southern teams have a bit of an edge for multiple Super Bowl wins. New York and New England are both northeastern teams and both have comparable declines in solar exposure as the season wears on. Is there a drop off in performance, as sunshine gets too weak to produce Vitamin D? More specifically, has there been any difference between the Patriots’ and Giants’ performance relative to the UV Index (UVI) over the course of the season?
The New England Patriots played their pre-season games at Tampa (UVI estimate = 11.7); versus Tennessee (7.5); at Carolina (8.8); and versus the New York Giants (6.9). The Pats started the regular season at the New York Jets (5.0) with a five-week moving average UVI of about 8.0. As the schedule unfolded in the fall, the UVI average steadily declined to 5.0 at the end of September; 4.5 at the end of October; 2.0 at the end of November; 1.5 at the end of December. Home field advantage kept the Patriots home in January and didn’t help with sun exposure.
Figure 1 summarizes the New England Patriots’ points scored, points allowed and total points over the course of the season as a function of the estimated 5 week moving average of the UV Index. A linear fit of the data is also shown to illustrate trends, though correlations are small since scores in any football game have a big standard deviation of approximately 14 points around the line. The trend lines show that the offense scored fewer points on average as the UVI declined, while the defense gave up more points. The Patriots had started the season blowing out opponents and beating the spread by a wide margin. While they ended the season unbeaten, the games were often much closer and results often fell short of Vegas’ expectations.
The New York Giants UVI also started high (7.8) and declined as expected during the fall into winter. However, the Giants had two playoff games in January that took them to Tampa Bay and Dallas where the solar intensity was much greater than what the Patriots experienced at home. The Giants’ offensive production trend (shown in Figure 2) decreased slightly as the UV Index declined. On defense the trend actually improved a bit (allowed fewer points) as a function of decreasing UVI.
Figure 2. Giants’ Offense Has Declined Slightly as UVI Declined.
With the Patriots’ 5 week moving average UVI currently at 2.0 they should win 32.4 - 18.0 over an average opponent. In contrast, the Patriots’ overall season average score was 35.6 - 17.0, Therefore based on UVI the Pats should under perform by 3.2 points on offense and 1.0 points on defense or a total of 4.2 points. As a result of the playoff games in the south, the Giants’ 5 week moving average UVI is currently 2.9. The linear fit in Figure 2 suggests they should beat an average opponent by 22.8 – 20.7. In contrast, the Giants’ overall season average score was 23.2 – 21.2. The Giants would be expected to under perform on offense by 0.4 points but make it up on defense. UVI exposure would appear to favor the Giants by nearly 4 points… not enough to offset the 12.5 point line for the game, but enough perhaps to make the game interesting.
While there isn't enough data here to draw any firm conclusions, the noticeable drop in the Pats' offensive production with declining UV Index levels suggests that Vitamin D levels could be a factor. Further research may shed light on this question but until then, Vitamin D should be monitored and supplements may be beneficial for maintaining peak performance.
| Date | NY Giants | UVI (5 week) | NE Patriots | UVI (5 week) |
|---|---|---|---|---|
| Sunday, 9/9 | at Dallas | 7.8 | at Jets | 8.0 |
| Sunday, 9/16 | GREEN BAY | 7.1 | SAN DIEGO | 6.8 |
| Sunday, 9/23 | at Washington | 6.6 | BUFFALO | 6.5 |
| Sunday, 9/30 | PHILADELPHIA | 6.2 | at Cincinnati | 5.0 |
| Sunday, 10/7 | NEW YORK JETS | 5.9 | CLEVELAND | 4.5 |
| Monday, 10/15 | at Atlanta | 5.4 | at Dallas | 4.6 |
| Sunday, 10/21 | SAN FRANCISCO | 4.8 | at Miami | 5.1 |
| Sunday, 10/28 | at Miami (London) | 4.5 | WASHINGTON | 4.4 |
| Sunday, 11/4 | BYE | 4.1 | at Indianapolis | 4.6 |
| Sunday, 11/11 | DALLAS | 3.7 | BYE | 4.2 |
| Sunday, 11/18 | at Detroit | 2.9 | at Buffalo | 3.3 |
| Sunday, 11/25 | MINNESOTA | 2.6 | PHILADELPHIA | 2.0 |
| Sunday, 12/2 | at Chicago | 2.1 | at Baltimore | 1.9 |
| Sunday, 12/9 | at Philadelphia | 1.9 | PITTSBURGH | 1.7 |
| Sunday, 12/16 | WASHINGTON | 1.6 | NY JETS | 1.5 |
| Sunday, 12/23 | at Buffalo | 1.4 | MIAMI | 1.6 |
| Saturday, 12/29 | NEW ENGLAND | 1.3 | vs NY Giants | 1.5 |
| Sunday, 1/6 | at Tampa Bay | 2.0 | BY | 1.4 |
| Sunday, 1/13 | at Dallas | 2.2 | JACKSONVILLE | 1.4 |
| Sunday, 1/20 | at Green Bay | 2.2 | SAN DIEGO | 1.4 |
| Sunday, 1/27 | BYE | 2.4 | BYE | 1.5 |
| Sunday, 2/3 | NE Patriots | 2.9 | NY Giants | 2.0 |
Friday, February 1, 2008
Sunshine and Star Football Recruits
With letter of intent day just around the corner, college football recruiters are making their final push to land the best prospects. Top kids are rated by the star system, with 3, 4 and 5 star athletes being the most sought after. As discussed in Football's Southern Exposure, the southern latitudes produce a greater than average share of football talent on a per capita basis. The same holds true for this year's national recruiting class as rated by Rivals.
There may be many reasons for the talent advantage in the south. Football may simply be more popular in the south. Warmer weather makes for a longer period of outdoor activity and practice. Simply spending more time in the sun leads to higher Vitamin D levels which can further boost athletic performance. As suggested by Dr. Cannell: Five converging—but totally separate—lines of scientific evidence leave little doubt that vitamin D improves athletic performance. Vitamin D is a potent steroid hormone that needs to be managed. Most people don't get enough sunshine especially in the north where the sun is too weak to produce Vitamin D in the winter.
The Rivals recruiting data base rates recruits by state. It's easy enough to calculate the number of top recruits (3, 4 and 5 star) per million population in each state and compare with the average amount of sunshine in the state (Ultra Violet Index). The top states are:
Figure 1 summarizes the number of 3 or more star rated recruits for all states for which Rivals rates football prospects. Figure 2 summarizes the number of 4 and 5 star recruits by state.
Figure 1. Correlation of Rivals 3, 4 and 5 Star Football Prospects with the UV Index.
Figure 2. Correlation of Rivals 4 and 5 Star Football Prospects with the UV Index.
The correlations evident in Figures 1 and 2 are quite significant. While it is well known that recruiting the south is important, if Vitamin D is a significant reason for the prolific production of top quality athletes, then those in the north should be able to enhance their prospects by better managing their Vitamin D intake.
So the most important star in the recruiting game may be the one most of us don't get enough of (at least in the northern latitudes). The UV Index is a measure of the potential for Vitamin D production. Vitamin D is a potent steroid hormone that is vital for good health and developing to one's fullest potential. While southern athletes have a natural advantage due to greater sun intensity, northern athletes can level the playing field by means of diet and supplements.
There may be many reasons for the talent advantage in the south. Football may simply be more popular in the south. Warmer weather makes for a longer period of outdoor activity and practice. Simply spending more time in the sun leads to higher Vitamin D levels which can further boost athletic performance. As suggested by Dr. Cannell: Five converging—but totally separate—lines of scientific evidence leave little doubt that vitamin D improves athletic performance. Vitamin D is a potent steroid hormone that needs to be managed. Most people don't get enough sunshine especially in the north where the sun is too weak to produce Vitamin D in the winter.
The Rivals recruiting data base rates recruits by state. It's easy enough to calculate the number of top recruits (3, 4 and 5 star) per million population in each state and compare with the average amount of sunshine in the state (Ultra Violet Index). The top states are:
| State | Population (Mil) | Rivals 3*,4*&5* | Athletes/Million | UVI |
|---|---|---|---|---|
| Louisiana | 4.29 | 38 | 8.86 | 8.36 |
| Mississippi | 2.91 | 25 | 8.59 | 7.75 |
| Alabama | 4.6 | 35 | 7.61 | 8.15 |
| South Carolina | 4.32 | 25 | 5.79 | 7.44 |
| Florida | 18.09 | 100 | 5.53 | 8.69 |
| Hawaii | 1.285 | 7 | 5.45 | 10 |
| Georgia | 9.36 | 50 | 5.34 | 7.37 |
| Arkansas | 2.81 | 13 | 4.63 | 7.06 |
| Ohio | 11.48 | 50 | 4.36 | 5.34 |
| Texas | 23.51 | 100 | 4.25 | 7.95 |
| Oklahoma | 3.58 | 15 | 4.19 | 6.88 |
| Virginia | 7.64 | 30 | 3.93 | 6.41 |
| Kansas | 2.76 | 9 | 3.26 | 6.4 |
| Arizona | 6.17 | 19 | 3.08 | 7.75 |
Figure 1 summarizes the number of 3 or more star rated recruits for all states for which Rivals rates football prospects. Figure 2 summarizes the number of 4 and 5 star recruits by state.
Figure 1. Correlation of Rivals 3, 4 and 5 Star Football Prospects with the UV Index.
Figure 2. Correlation of Rivals 4 and 5 Star Football Prospects with the UV Index.
The correlations evident in Figures 1 and 2 are quite significant. While it is well known that recruiting the south is important, if Vitamin D is a significant reason for the prolific production of top quality athletes, then those in the north should be able to enhance their prospects by better managing their Vitamin D intake.
So the most important star in the recruiting game may be the one most of us don't get enough of (at least in the northern latitudes). The UV Index is a measure of the potential for Vitamin D production. Vitamin D is a potent steroid hormone that is vital for good health and developing to one's fullest potential. While southern athletes have a natural advantage due to greater sun intensity, northern athletes can level the playing field by means of diet and supplements.
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