european college of sport science

Thursday, June 25th, 2009
DOES PRECOOLING IMPROVE 1500 M SWIMMING PERFORMANCE?
KOCJAN, N., BOGERD, C.P., ALLENSPACH, P., PERRET, C., ROSSI, R.M.
EMPA, SWISS FEDERAL LABORATORIES FOR MATERIALS TESTING AND RESEARCH
Introduction: The literature suggests that precooling can increase exercise performance in a warm ambient. In particular, this is true for
cycling and running performance (1, 2). However, it is unclear how precooling affects swimming performance. The present study aimed to
investigate the effect of precooling on 1500 m swimming performance.
Methods: Eight subjects, 4 female and 4 male triathletes, participated in the study. Their average ± SD age was 29 ± 6 yr., height 173 ± 11
cm, weight 69.3 ± 12.1 kg and VO2peak 60.2 ± 6.3 ml•min-1•kg-1. Control (CON) and precooling (COOL) trials were performed on the
same time of a day, at least one week apart. Both trials consisted out of: i)10 min warm-up at 40% of subject’s VO2peak on a cycleergometer,
followed by ii) 1500 m swimming at competition speed in water with the temperature of 27.6 ± 0.1 °C. In addition, during
COOL trial subjects wore an ice vest (Arctic Heat, Burleigh Heads, QLD, Australia) 35 min preceding the warm-up and during the warmup.
During the trials, gastrointestinal temperature (Tc) and skin temperature on four body locations (Tsk) were continually registered. In
addition, the subjects were asked to rate their thermal perception (TP) prior the warm-up and post swimming. Finally, the time for swimming
1500 m was noted.
Results: The effect of precooling was reflected in a significant 0.17 ± 0.18 ºC decrease (p=0.045) in Tc and a 0.79 ± 0.33 ºC decrease in Tsk
(p=0.001). Lower Tc, observed for COOL trial, persisted till the end of swimming. In particular, Tc at the end of swimming was 37.89 ± 0.34
ºC in COOL and 38.31 ± 0.34 ºC in CON (p=0.049). In contrast, Tsk was not significantly different at the end of swimming among the trials.
Prior to swimming, subjects rated TP in CON and COOL as slightly warm (1 ± 1) and cool (-2 ± 1; p=0.015), respectively. Likewise, at the end
of swimming, subjects rated TP in CON trial as hot (3 ± 1), while in COOL trial as warm (2 ± 1; p=0.021). The swimming performance was
with 22:29 ± 2:00 min significantly shorter in COOL trial compared to 23:04 ± 2:02 min observed for CON trial (p=0.014).
Conclusion
The observed results suggest that precooling with an ice vest, prior and during the warm-up significantly decreases Tc. Since lower Tc
persisted through swimming it is suggested that this effect enables subjects to improve swimming performance.
References
1.Marino FE. Methods, advantages, and limitations of body cooling for exercise performance. Br J Sports Med 36: 89-94, 2002.
2.Quod MJ, Martin DT, and Laursen PB. Cooling athletes before competition in the heat: comparison of techniques and practical considerations.
Sports Med 36: 671-682, 2006.
THE EFFECT OF WORKING IN A HOT ENVIRONMENT ON MARKERS OF THE IMMUNE RESPONSE: AN OIL AND GAS
INDUSTRY STUDY
KNEZ, W.L., RACINAIS, S., GIRARD, O., WALSH, A., GAOUA, N., GRANTHAM, J.
ASPETAR, QATAR ORTHOPAEDIC AND SPORTS MEDICINE HOSPITAL
Introduction: Physical activity in a high ambient temperature in comparison to neutral conditions has been demonstrated to impact on a
number of immune markers. However, recent research shows little support for the previously held contention that physical activity in a hot
environment further compromises the immune system in comparison to a neutral environment. However, due to ethical restrictions in
laboratory-based research, investigations are limited to acute exposures of extreme heat. Indeed, some occupations involving fire fighters,
soldiers and miners are required to live and/or work in extreme conditions. Subsequently, this study sought to determine the chronic
effect of living and working in an extremely hit environment on immune system markers.
Method: The present study examined 30 apparently healthy (125/77 ± 11/9 mmHg systolic and diastolic blood pressure) male participants
in hot (August; 410C) and neutral (January; 220C) conditions. Throughout the day, changes in core temperature were assessed by ingestible
pills. In addition, blood was sampled from the antecubital vein before (5:30am to 7:00am) and after (3:30 to 5:00pm) their working
day to assess changes in immune markers. A two-way repeated measures ANOVA was used to determine significant main effects and
interactions.
Results: Mean core temperature was significantly (p