Kava (sakau, Piper methysticum) impact on running times

In the spirit of Piaget I have studied a subject close at hand - myself. As far as I know I am the only person on this island who runs somewhat regularly and who also drinks Pacific island kava (Piper methysticum, sakau) with some frequency. During the period from 27 June 2008 to 27 November 2008 I ran on 91 of the 154 days. During this same period I consumed kava on fifteen occasions. This is in no way any type of controlled experiment, there was no attempt to ensure regular kava consumption on any sort of schedule. The period covers 22 weeks, thus on average I consumed kava at a rate of roughly once every week and a half. This consumption, however, is not evenly spaced at once every week and a half. As noted in the opening sentence, this is simply my ordinary life under study.

Anecdotally I am self-aware that kava leaves my running feeling lethargic for up to four days post-kava. I now have enough data to run an analysis looking at whether there is a post-kava dip in performance as indirectly measured by my average running time in the days post-kava consumption.

While such a self-absorbed study must seem rather silly, the consumption of kava occurs across the Pacific. With an increasing emphasis on treating metabolic syndrome and life style related diseases with exercise, data on the potential impact of kava consumption on exercise recommendations made by physicians should have some value. Obviously physicians would probably prefer that their patients cease the consumption of kava, and abstinence is the best health policy. Despite the doctor's recommendation, many will probably continue their consumption of kava.

In order to perform the analysis, I looked at the average number of minutes of running per day in the days after a kava sessions. As an evening runner, an evening kava session means a day without running. Day "n" refers to the day of kava consumption, hence the zero average for day n. Day n+1 is the day after kava consumption, n+2 two days after. This is compared to my average running duration in minutes for days on which I do not drink kava (31 minutes). Note that this is not to say I run every day for 31 minutes - bear in mind that only 91 of 154 days are days on which I ran. An additional complication is that day n+1 is also a day without kava on which running could occur, so the 31 minute average includes immediately post-kava days. The thirty-one minutes can be thought of as a functional base line. The following chart shows my recovery to base line post-kava.

Post-kava consumption the average number of minutes rises logarithmically, 
 crossing the overall average of 31 minutes at the six day mark.

Note that based on a logarithmic best-fit line, I do not return to my base line duration in minutes of running until six days post-kava. This is a longer impact than the four days I had thought would be the case.

That the logarithmic best fit then rises above base is not an indication of some form of "rebound" above the mean. A logarithmic function best fits the data but rises without limit whereas my running has a long term average of thirty-one minutes. At n+9 and beyond the duration of my runs simply returns to the long term non-kava influenced average.

There are many caveats to this thoroughly unscientific study. The low average duration of running minutes post-kava is not due to short runs. The low average is because I rarely run on a day n+1. The causes are many - gas from the hibiscus bark, "oan sakau" (a form of kava hangover), a tendency to nap through my running time the next day, and general lethargy. When I do run, my median running time is 48 minutes, my shortest runs are typically 24 to 28 minutes, and I never run for less than 20 minutes. Thus the fourteen minute average on day n+1 is a result of many n+1 days on which I did not run (days of 0 minutes of running).

Another caveat is that I have quite intentionally been exploring the impact of varying amounts of kava consumption. A light night is two cups of Kitti kava, a heavy night is four cups or drinking at a "stone" based market. I am almost always "wiped out" the day after a "heavy" night and unable to run. On only four of ten days post-heavy kava consumption was I able to run. Unfortunately the sample size is too small to carry any statistical significance.

Sample size plagues the post-light kava data as well. I have only two of those evenings in the data set, and my running rate on day n+1 is 50%. The remaining three evening of kava were three cup evenings that lie between light and heavy consumption.

I would be remiss if I did not note than an earlier informal study of kava consumption at "cup" based markets in Kitti - where I consumed my kava - showed an average of 3.27 cups consumed per customer per evening, with a median of 3 and a mode of 1. In that mode of one cup is some encouragement as that is a very light level of consumption.

Of course many locals drink regularly and yet work on the farm with great vigor the next day - nothing in my data extrapolates beyond this single runner. Still, in what I perceive to be the absence of data there may be value in this single data point. Of note is that a once a week kava drinker potentially impacts their athletic performance capability for six days - and on the seventh day the drinker is consuming kava yet again. This suggests that a once-a-week regular, such as an "every Friday night" drinker, may never fully recover their full exercise capacity.

I apologize for the rather anecdotal and nonscientific nature of this very informal study. As I noted, the number of people who both run and drink kava is rather small. In the small circles in which I move I seem to be the only person who can be found in a market in Kitti drinking kava and running in a local 5k race on a Saturday morning. I occasionally see other kava consumers out walking on the causeway or up at the track, but never do I see them running.

For those unfamiliar with my own background in running and kava drinking, I have been running since 1978 and consuming kava somewhat regularly since 1992. In the summer of 2001 I engaged in a one-off experiment in every night kava consumption. Although I was starting my consumption well after the typical time of my evening run, I found I was completely unable to run. Beyond the post-kava issues cited above were additional issues. I was unable to cool properly due to changes in my skin (dryness) and my hydration levels were not ideal. For me, that "experiment" ruled out the possibility that an every night "heavy" drinker could engage in meaningful levels of intense exercise. At that time in 2001 I had felt that a "once a week" drinker might be able to balance kava drinking and athleticism, the above data casts doubt on that premise.

Dana Lee Ling