The prevalence of intravenous (IV) fluid hydration practices by athletes has not been previously documented. In this issue, Fitzsimmons et al1 provide findings of a survey administered to all 32 National Football League (NFL) teams. They found that 3 of 4 teams give IV “pregame hyperhydration” infusions to their players. This report of widespread use of IV fluid is not surprising given this practice is often observed during half-time breaks and reported during television coverage. It would have been further enlightening had the survey included IV administration during and after games and during training. It is important to note, particularly for readers of the Clinical Journal of Sport Medicine, that the use of IV infusions both in competition and out of competition has been banned by the World Anti-Doping Agency (WADA) since 2005. This was not acknowledged or discussed by the authors. The World Anti-Doping Agency's List of Prohibited Methods, Chemical and Physical Manipulation (Section M2), states, “Intravenous infusions are prohibited except for those legitimately received in the course of hospital admissions or clinical investigations.”2 Fitzsimmons et al report that up to 20 players on a team are administered 1.5 L of normal saline 2 hours before a game; this clearly does not meet this indication.
The World Anti-Doping Agency has justified the inclusion of IV infusions on the prohibited list because of the presumed intent of athletes to manipulate their hematocrit or hemoglobin levels in an effort to circumvent the no-start rules implemented by some sports federations. Additional WADA concerns are that IV access could provide a route for administering prohibited substances, that IV fluids could be used to mask prohibited substances, and that athletes may attempt accelerated weight loss regimens to make the correct weight for a competition before using IV infusion to rapidly rehydrate, thus provoking health and safety concerns.3 Although not all of these considerations may apply to the NFL, it is surprising that this procedure is openly practiced by the NFL teams.
As with many practices used by elite athletes to gain an advantage, the evidence base to support the use of IV fluids is nonexistent. As noted by Fitzsimmons et al,1 only 1 study has compared exercise capacity following pre-exercise IV hyperhydration versus commencing exercise in a euhydrated state; no cardiovascular, thermoregulatory, or performance benefits were found.4 Fitzsimmons et al accurately summarize the handful of small studies showing that the administration of IV fluid confers no advantage over oral fluid ingestion in improving physiological function when used during rehydration. In fact, several of these rehydration studies have indicated that oral intake is actually superior to IV administration of fluid. In considering the effects of IV fluid administration on exercise performance, the literature is sparse, but there is no demonstrable benefit of such practice when compared with the administration of oral fluids. Clearly, with only a small number of studies in the area, more research is required to evaluate the benefit and risks associated with this strategy.
Another point briefly discussed by Fitzsimmons et al that requires deeper consideration is the equivocal benefit of hyperhydration. Our recent review reported that glycerol hyperhydration is capable of increasing body water by up to approximately 1.5 L for several hours, depending on the protocol employed.5 However, any benefit derived from this practice depends on the subsequent exercise mode, intensity, duration, and environmental conditions. Cardiovascular (eg, reduced exercise heart rate), thermoregulatory (eg, increased sweat rate and forearm blood flow), and performance (eg, increased endurance capacity, work, and power) responses have all been reported in approximately half of the published studies. These benefits are generally only seen, however, when the ensuing exercise is continuous at a high intensity, is performed in thermally stressful conditions (eg, 30-35°C, 30%-60% relative humidity), and is likely to induce a weight loss of >2% body weight. Given the characteristic stop-start nature of the exercise load of an NFL game and the ability of football players to drink regularly, the benefit to be gained from the pre-accumulation of large volumes of fluid is questionable, based on the evidence.
A notable finding of this study was that almost half of the respondents reported a complication as a consequence of the IV procedure. This is of great concern because of the risks to the health of the participants, an aspect of concern surrounding this practice raised by WADA. In Australia, this practice has been banned by the Australian Football League following a media report that a professional team was administering IV fluids. Among the justifications for the ban were concerns that this practice would lead to use by nonprofessional less-resourced football teams. In these situations, appropriate medically trained staff might not be available to conduct the procedure in a safe hygienic way, leading to a greater complication rate. It would be interesting to determine whether the use of IV fluids in the NFL, and the noted complications, has been associated with any adverse health outcomes or has lead to copycat behavior in less professional sporting environments.
The results of the survey by Fitzsimmons et al confirm the widespread use of an otherwise banned, seemingly ineffective, and potentially dangerous medical procedure. It will be interesting to see how WADA and the NFL respond.
1. Fitzsimmons S, Tucker A, Martins D. Seventy-five Percent of NFL teams use pregame hyperhydration with intravenous fluid. Clin J Sports Med
4. Hostler D, Gallagher M Jr, Goss FL, et al. The effect of hyperhydration on physiological and perceived strain during treadmill exercise in personal protective equipment. Eur J Appl Physiol