Excessive training is reported to cause sleep disturbances and mood changes. We examined sleep and psychological changes in female swimmers across a competitive swimming season, that is, at the start of the season (onset), during peak training period (peak), and after a precompetition reduction in training (taper). For each phase, polysomnographic recordings, body composition, psychological parameters, and swimming performance were obtained. A daily training log and sleep diary were maintained for the entire study period. Sleep onset latency (SOL) time awake after sleep onset, total sleep time (TST), and rapid eye movement (REM) sleep times were similar at all three training levels. Slow wave sleep (SWS) formed a very high percentage of total sleep in the onset (26%) and peak (31%) training periods, but was significantly reduced following precompetition taper (16%), supporting the theory that the need for restorative SWS is reduced with reduced physical demand. The number of movements during sleep was significantly higher at the higher training volumes, suggesting some sleep disruption. In contrast to other studies, mood deteriorated with a reduction in training volume and/or impending competition.

Primary dysmenorrhea is characterized by painful uterine cramps, near and during menstruation, that have an impact on personal life and productivity. The effect on sleep of this recurring pain has not been established. We compared sleep, nocturnal body temperatures, and hormone profiles during the menstrual cycle of 10 young women who suffered from primary dysmenorrhea, without any menstrual-associated mood disturbances, and 8 women who had normal menstrual cycles. Dysmenorrheic pain significantly decreased subjective sleep quality, sleep efficiency, and rapid eye movement (REM) sleep but not slow wave sleep (SWS), compared with pain-free phases of the menstrual cycle and compared with the controls. Even before menstruation, in the absence of pain, the women with dysmenorrhea had different sleep patterns, nocturnal body temperatures, and hormone levels compared with the controls. In the mid-follicular, mid-luteal, and menstrual phases, the dysmenorrheics had elevated morning estrogen concentrations, higher mean in-bed temperatures, and less REM sleep compared with the controls, as well as higher luteal phase prolactin levels. Both groups of women had less REM sleep when their body temperatures were high during the luteal and menstrual phases, implying that REM sleep is sensitive to elevated body temperatures. We have shown that dysmenorrhea is not only a disorder of menstruation but is manifest throughout the menstrual cycle. Furthermore, dysmenorrheic pain disturbs sleep, which may exacerbate the effect of the pain on daytime functioning.

OBJECTIVE: To investigate the effects of altered feeding frequencies on the relationship between perceived hunger and subsequent food intake and appetite control in obese men. DESIGN: Obese men reported in a fasted state in the morning to the laboratory where an isoenergetic pre-load (4100 AE 234 kJ, which was 33% average daily energy requirement (ADER) of each subject) comprising 70% carbohydrate, 15% protein, and 15% fat was given. This was administered either as a SINGLE meal, or divided evenly over 5 meals given hourly as a MULTI feeding pattern. Five hours after the ®rst pre-load, an ad libitum test meal was given to determine whether there was a difference in the amount of energy that was consumed between the two eating patterns. SUBJECTS: Seven non-diabetic, non-smoking, unrestrained obese men (age 37.4 AE 18.5; BMI 40.02 AE 10.93 kgam 72 ) were recruited for this study. Subjects were not told the precise reasons for this study but rather were informed that changes in blood glucose, insulin and free fatty acids with meal frequency were to be monitored. MEASUREMENTS: Blood glucose, serum insulin and free fatty acid (FFA) concentrations, and visual analogue scales (VAS) were measured prior to commencing the feeding regime and thereafter hourly for 5 h. Thereafter an adlibitum meal was given. The weight (and energy content) of the food consumed, and the time taken to eat lunch were recorded. Following this ad libitum lunch, the same variables were determined again (15, 45, and 75 min post-test meal). RESULTS: When given a SINGLE pre-load, 27% more (t 2.651; P`0.05) energy was consumed in the ad libitum test meal (5261 AE 1289 kJ) compared to that eaten after the MULTI pre-load (3763 AE 1986 kJ). This increase in food intake occurred despite no signi®cant change in subjective hunger ratings. Over the 315 min pre-load period, peak insulin concentrations were signi®cantly higher (F 6,72 7.95, P`0.01) on the SINGLE treatment (171.2 AE 129.8 mU ml 71 ) than on the MULTI treatment (133.7 AE 70.2 mU ml 71 ). Serum insulin remained elevated for longer on the MULTI meal treatment, resulting in no difference in the area under the insulin curves between the two feeding treatments. There was a positive correlation (r 0.87) between the amount of energy consumed at lunch and insulin concentration before lunch in the SINGLE group. However, this relationship was not apparent when subjects were given the MULTI meal preload. CONCLUSION: Obese males fed an isoenergetic pre-load sub-divided into a multi-meal plan consumed 27% less at a subsequent ad libitum test meal than did the same men when given the pre-load as a single meal. Prolonged but attenuated increases in serum insulin concentration on the multi-meal programme may facilitate this acute reduction in appetite.

Four trained young men worked for 4 h/day at 40-50% of their maximum aerobic capacity first for 3 days at 25 degrees C db, 18 degrees C wb, and then for 10 consecutive days at 45 degrees C db, 32 degrees C wb. This portion of the study was mainly concerned with central circulatory changes during acclimatization. The central circulatory adaptation to work in heat could be divided into four distinct phases: phase I (day 1) was characterized by a progressive fall in stroke volume (SV) during heat exposure but cardiac output (CO) was maintained above control values by high heart rates. Phase II (days 2 and 3) was marked by increases in SV ande decreases in heart rate but with little change in CO from phase I. During phase III (days 4-8 of acclimatization), CO increased due to increases in SV. Phase IV (days 6-8) was associated with decreases in rectal and skin temperature towards control levels. SV and HR both decline in this phase so that CO was not elevated greatly above control levels. The results indicated that central circulatory and temperature regulating events are not casually associated in acclimatization.

Four trained young men, worked for 4 h/day at 43-50% of their maximum aerobic capacity for 3 days at 25 degrees C db, 18 degrees C wb and then for 10 consecutive days at 45 degrees C db, 32 degrees C wb. Their thermal status was assessed using direct calorimetry. As a group, the men showed classical acclimization responses, but there were marked individual differences. The calorimetric analysis revealed that reductions in strain were associated with minor changes in heat balance confined to the first and last hours of exposure. Events occurring within the first 4 days appeared to have little effect on body temperatures. Significant decreases in body temperature took place only when sweat and evaporation rate increased. A 10% increase in evaporation rate was accompanied by a 30% increase in sweat rate and a 200% increase in unevaporated sweat; thus, there is a wasteful overproduction of sweat. By the 10th day skin temperature was confined to the level necessary to evaporate sufficient sweat to achieve thermal balance with a fully wet body surface. The efficiency of heat transport within the body did not change with acclimatization.