Sweat lactate response during cycling at 30°C and 18°C WBGT

Sweat lactate reflects eccrine gland metabolism. However, the metabolic tendencies of eccrine glands in a hot versus thermoneutral environment are not well understood. Sixteen male volunteers completed a maximal cycling trial and two 60-min cycling trials [30°C?=?30±1°C and 18°C?=?18±1°C wet bulb globe temperature (WBGT)]. The participants were requested to maintain a cadence of 60 rev?·?min^?1 with the intensity individualized at ～ 90% of the ventilatory threshold. Sweat samples at 10, 20, 30, 40, 50 and 60?min were analysed for lactate concentration. Sweat rate at 30°C (1380±325?ml?·?h^?1) was significantly greater (P<0.05) than at 18°C (632±311?ml?·?h^?1). Sweat lactate concentration was significantly greater (P<0.05) at each time point during the 18°C trial, with values between trials tending to converge across time. During the 30°C trial, both heart rate (20, 30, 40, 50 and 60?min) and rectal temperature (30, 40, 50 and 60?min) were significantly higher than in the 18°C trial. Higher sweat lactate concentrations coupled with lower sweat rates may indicate a greater relative contribution of oxygen-independent metabolism within eccrine glands during exercise at 18°C. Decreases in sweat lactate concentration across time suggest either greater dilution due to greater sweat volume or increased reliance on aerobic metabolism within eccrine glands. The convergence of lactate concentrations between trials may indicate that time-dependent modifications in sweat gland metabolism occur at different rates contingent partially on environmental conditions.     

Fathers online: learning about fatherhood through the internet

In the transition to fatherhood, men face numerous challenges. Opportunities to learn new practices and gain support are limited, although the provisions of father-specific spaces such as fathers' antenatal classes or "responsible fathering" programs are important advances. This article explores how men use the social space of a father-specific Internet chat room to learn about fathering. Messages to an Australian-hosted, father-specific chat room (for fathers of infants or young children) were examined, and three overlapping themes illustrated men's perceptions of their transition to fatherhood. The themes concerned recognition of and response to a lack of social space, services, and support for new fathers. The implications for fathers' perinatal education are discussed.