The effects of two nights of sleep deprivation with or without energy restriction on immune indices at rest and in response to cold exposure

Abstract

The purpose of the study was to determine the effects of two nights of sleep deprivation with or without energy restriction on immune indices at rest and in response to cold exposure. On three randomised occasions ten males slept normally [mean (SD): 436 (21) min night(-1); CON], were totally sleep-deprived (SDEP), or were totally sleep-deprived and 90% energy-restricted (SDEP + ER) for 53 h. After 53 h (1200 h) participants performed a seated cold air test (CAT) at 0.0 degrees C until T (re) decreased to 36.0 degrees C. Circulating leucocyte counts, neutrophil degranulation, stress hormones and saliva secretory IgA (S-IgA) were determined at 0 h, 24 h, 48 h, pre-CAT, post-CAT, 1-h and 2-h post-CAT. One night on SDEP increased bacterially stimulated neutrophil degranulation (21%, P < 0.05), and two nights on SDEP and SDEP + ER increased S-IgA concentration (40 and 44%; P < 0.01). No other significant effects were observed for immuno-endocrine measures prior to CAT. CAT duration was not different between trials [mean (SD): 133 (53) min] and T (re) decreased to 35.9 (0.3) degrees C. Modest whole-body cooling decreased circulating lymphocyte counts (25%; P < 0.01), S-IgA concentration (36%; P < 0.01) and secretion rate (24%; P < 0.05). A neutrophilia occurred post-CAT on CON and SDEP and 2-h post-CAT on SDEP + ER (P < 0.01). Modest whole-body cooling also decreased neutrophil degranulation on CON (22%) and SDEP (18%; P < 0.05). Plasma cortisol and norepinephrine increased post-CAT (31 and 346%, P < 0.05), but modest whole-body cooling did not alter plasma epinephrine. In conclusion, two nights of SDEP or SDEP + ER did not compromise resting immune indices. However, modest whole-body cooling (T(re) 35.9 degrees C) decreased circulating lymphocytes, neutrophil degranulation and S-IgA, but responses were not amplified by prior SDEP or SDEP + ER.

Effect of daily mixed nutritional supplementation on immune indices in soldiers undertaking an 8-week arduous training programme

“…Unstimulated whole saliva samples were collected from participants using a passive dribble for 5 min into a preweighed universal tube (HR 120-EC, A & D instruments, Tokyo, Japan) between 0530 and 0600 hours at baseline, pre-Weld exercise and post-Weld exercise (Costa et al 2010). All saliva samples were collected while the participant sat quietly after Wrst rinsing their mouth with water and swallowing.…”

Acute cold stress and mild hypothermia impact on short-term, working memory and attention

“…However, it is well known that acute cold stress exposure increases the levels of catecholamine (Srámek et al, 2000; PalmieriSmith et al, 2007) and other stress hormones (Sramek et al, 2000;Pilcher et al, 2002;LaVoy et al, 2011) which impairs cognitive performance (Elzinga et al, 2005;Robinson et al, 2008). Furthermore, very mild decreases in core temperature (~0.5 °C) have little or even stimulatory effects on the immune function (Brenner et al, 1999), but the modest (~1 °C) decreases in core temperature have depressive effects on the immune function (Costa et al, 2010). Sandi and Pinelo-Nava (2007) showed that the effect of stress exposure on learning and memory is complex and is determined by the factors such as the length of stress exposure, nature of the stress stimulus, specific cognitive function examined, age and gender.…”

“…Accordingly, we assume that cold exposure, limited by time in earlier studies, might induce different responses on T re and subject's cognitive function could be affected differently. According to cold stress studies the modest (~1 °C) decreases in core temperature have depressive effects on the immune function (Costa et al, 2010), increases the levels of catecholamine (Srámek et al, 2000;Palmieri-Smith et al, 2007) and other stress hormones (Srámek et al, 2000;Pilcher et al, 2002;LaVoy et al, 2011), thus we hypothesized that the method used in our study (exposure to cold-water limited by 3 Cold impact on cognitive function the set point of T re 35.5 °C) should induce high cold stress and manifest cognitive performance on tests involving memory and attention. (McArdle et al, 1984) using a medical skinfold caliper (Seahan, SH5020, Masan, Korea).…”

“…All subjects dropped T re to 35.5 °C (necessary condition) and the average of T re decrement was 1.54 ± 0.06 °C, which indicates that deep body cooling had initiated. According to cold stress studies the modest (~1 °C) decreases in core temperature have depressive effects on the immune function (Costa et al, 2010), increases the levels of catecholamine (Srámek et al, 2000;Palmieri-Smith et al, 2007) and other stress hormones (Srámek et al, 2000;Pilcher et al, 2002;LaVoy et al, 2011). We did not took the blood samples, but calculated that our used single passive cooling procedure induced a very similar level of cold stress for all subjects (the mean CSI resulted as high as 7.02 ± 0.22).…”

Two nights of sleep deprivation with or without energy restriction does not impair the thermal response to cold

“…Thereafter, nude body mass, blood and urine samples were collected at 24 h, 48 h, immediately before the CAT, and immediately after the CAT. The blood samples obtained were predominantly for the assessment of immune function as reported previously (Costa et al 2010). At 1200 h on day one (5 h into each trial) and day two (29 h into each trial), participants performed a 90 min steady state walk at 50% VO2max, followed by a 15 min seated rest and then a 5 km time trial.…”