Saturday, January 26, 2008

Sunshine and Super Bowl XLII

When it comes to peak athletic performance, it doesn’t get much better than the Super Bowl. Table 1 lists the 21 (of 32) NFL teams that have at least one win or two appearances in past Super Bowls. New England and New York are both among the top teams. The Patriots are now tied for second with 6 total Super Bowl appearances while the Giants move up to a tie for fourth with 4 appearances.

We’ve seen in an earlier post Football’s Southern Exposure that the sunny southern states produce more quality college football players per capita than the dimmer northern states. But the pros can draft the best talent and level the playing field. So one might wonder if there is any additional benefit from normal sunlight exposure for NFL teams.

Figure 1 summarizes the number of Super Bowl appearances as a function of each team’s potential sunshine exposure. The straight line fit to the data has a positive tilt as the UV Index goes up. Wins follow a similar pattern with a slightly better positive correlation (R-squared = 0.05). Even a small correlation is worth noting in a game where a slight edge can make a difference in the outcome of a game. All else being equal, the correlation would vanish if a low UVI team had 4 more wins at the expense of a high UVI team, e.g. if the Jets had 5 wins instead of 1 and Dallas had 1 win instead of 5. A swing of four Super Bowl wins out of 41 played is roughly a 10% factor.

It's quite possible that the four game tilt favoring sunnier NFL teams is just due to luck. Or it may be that the sunshine factor, Vitamin D, is essential for peak athletic performance. Northern teams' Vitamin D levels may drop more than southern teams. In the winter months UV Levels in northern cities such as New York and Boston fall substantially below the point where the sun can produce Vitamin D in the skin.

However, there is no magic bullet here for handicapping the outcome of Super Bowl XLII as the difference in UV Index between New York and Boston isn't much of a factor. While the Giants may have benefited from recent road games in Tampa and Dallas, both teams will have a chance to catch some rays in the Arizona sunshine prior to the big game.

Figure 1. NFL Super Bowl Appearances are
Positively Correlated with UV Index

Most of the credit for Super Bowl wins has traditionally gone to the quarterbacks. Multiple-win quarterbacks have become near legendary in status. Here’s a summary of multiple Super Bowl winning QBs, and their birth states:

Pittsburgh Steelers: Terry Bradshaw, Louisiana – 4 wins
San Francisco; Joe Montana, Pennsylvania – 3 wins
Dallas Cowboys: Troy Aikman, Southern California – 3 wins
New England: Tom Brady, California (SF Bay area) – 3 wins
Denver Broncos: John Elway, Washington – 2 wins
Miami Dolphins: Bob Griese, Indiana – 2 wins
Oakland/LA Raiders: Jim Plunkett, California (SF Bay area) – 2 wins
Green Bay Packers: Bart Star, Alabama – 2 wins
Dallas Cowboys: Roger Staubach, Ohio – 2 wins

Does the sunshine factor come into play with these elite athletes? There is in fact a tilt or correlation between the number of Super Bowl wins and increased exposure to Ultra Violet light in the quarterbacks’ original home states. While there isn’t enough data here to be statistically significant, there’s no need to wait several more decades for absolute proof. Managing Vitamin D through sun exposure, diet or supplements is prudent based on the overwhelming evidence of reduced risk of chronic diseases even if it won’t make you a superstar athlete. But if you happen to be Eli Manning, well maybe you can become the next legend.

Figure 2. NFL Quarterbacks’ Super Bowl Wins are
Correlated With Birth State UV Index

Table 1: NFL Super Bowl Record
(Teams with at least one win or two appearances)

Team Wins Losses Days/Year UVI>6
Dallas Cowboys 5 3 183
Pittsburgh Steelers 5 1 113
New England Patriots 3 2 102
Denver Broncos 2 4 162
San Francisco 49ers 5 0 156
Oakland Raiders 3 2 156
Washington Redskins 3 2 131
Miami Dolphins 2 3 262
Green Bay Packers 3 1 101
New York Giants 2 1 103
Buffalo Bills 0 4 97
Minnesota Vikings 0 4 94
Indianapolis Colts 2 1 111
St. Louis Rams 1 2 125
Chicago Bears 1 1 105
Kansas City Chiefs 1 1 136
Cincinnati Bengals 0 2 101
Philadelphia Eagles 0 2 114
Baltimore Ravens 1 0 129
New York Jets 1 0 103
Tampa Bay Buccaneers 1 0 239

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