A single session of intense exercise improves the inflammatory response in healthy sedentary women

Physical activity has a great capacity for modulating the immune system, including the inflammatory response. However, the effects of exercise on the inflammatory response have rarely been studied in women, even though women are more susceptible than men to chronic inflammatory diseases. The aim of this study was to ascertain the effect of single sessions of exercise on the inflammatory response of sedentary women, evaluating neutrophil function and circulating concentrations of inflammatory cytokines. Exercise consisted of one session of cycling (1 h at ~70% of VO₂ max) on a cycle ergometer. Blood samples were taken in the basal state and immediately after the exercise session. Neutrophil function was studied on isolated cells by evaluating their phagocytic capacity against latex beads and their oxygen-dependent microbicidal capacity as reflected in the superoxide anion (O₂ ⁻) production. Circulating inflammatory cytokines were determined using a novel antibody-based protein micro-array method. The circulating concentration of IL-8 (a stimulatory cytokine for neutrophils) was also determined by ELISA. Exercise increased the phagocytic and the oxygen-dependent microbicidal capacities of neutrophils in the sedentary women. No variations were found in IL-2, IL-3, IL-5, IL-6, IL-7, IL-8, IL-10, IL-13, IFN-γ, TNF-α and -β, TGF-β, MCP-2 and -3, MIG, G-CSF, and GM-CSF. However, while the circulating concentrations of GRO and MCP-1 increased after exercise, there was a decrease in that of RANTES, a pro-inflammatory cytokine. Exercise improves neutrophil function, possibly mediated, at least partially, by GRO (a potent neutrophil activator) but not by IL-8. This stimulation of neutrophil function does not seem to be accompanied by any harmful systemic inflammatory response since no changes in the main pro-inflammatory cytokines were observed, and there was a decrease in RANTES.     

The effects of intensity of exercise on excess postexercise oxygen consumption and energy expenditure in moderately trained men and women

This experiment investigated the effects of intensity of exercise on excess postexercise oxygen consumption (EPOC) in eight trained men and eight women. Three exercise intensities were employed 40%, 50%, and 70% of the predetermined maximal oxygen consumption (VO_2max). All ventilation measured was undertaken with a standard, calibrated, open circuit spirometry system. No differences in the 40%, 50% and 70% VO_2max trials were observed among resting levels of oxygen consumption (V0₂) for either the men or the women. The men had significantly higher resting VO₂ values being 0.31 (SEM 0.01) 1·min^–1 than did the women, 0.26 (SEM 0.01) 1·min^–1 (P < 0.05). The results indicated that there were highly significant EPOC for both the men and the women during the 3-h postexercise period when compared with resting levels and that these were dependent upon the exercise intensity employed. The duration of EPOC differed between the men and the women but increased with exercise intensity: for the men 40% – 31.2 min; 50% – 42.1 min; and 70% – 47.6 min and for the women, 40% – 26.9 min; 50% – 35.6 min; and 70% – 39.1 min. The highest EPOC, in terms of both time and energy utilised was at 70% VO_2max. The regression equation for the men, where y=O₂ in litres, and x=exercise intensity as a percentage of maximum was y=0.380x + 1.9 (r ²=0.968) and for the women is y=0.374x–0.857 (r ²=0.825). These findings would indicate that the men and the women had to exercise at the same percentage of their VO_2max to achieve the maximal benefits in terms of energy expenditure and hence body mass loss. However, it was shown that a significant EPOC can be achieved at moderate to low exercise intensities but without the same body mass loss and energy expenditure.     

Evaluation of the American College of Sports Medicine submaximal treadmill running test for predicting VO2max

The purpose of this study was to assess the validity of the American College of Sports Medicine's (ACSM's) submaximal treadmill running test in predicting VO2max. Twenty-one moderately well-trained men aged 18-34 years performed 1 maximal treadmill test to determine maximal oxygen uptake (M VO2max) and 2 submaximal treadmill tests using 4 stages of continuous submaximal exercise. Estimated VO2max was predicted by extrapolation to age-predicted maximal heart rate (HRmax) and calculated in 2 ways: using data from all submaximal stages between 110 b·min(-1) and 85% HRmax (P VO2max-All), and using data from the last 2 stages only (P VO2max-2). The measured VO2max was overestimated by 3% on average for the group but was not significantly different to predicted VO2max (1-way analysis of variance [ANOVA] p = 0.695; M VO2max = 53.01 ± 5.38; P VO2max-All = 54.27 ± 7.16; P VO2max-2 = 54.99 ± 7.69 ml·kg(-1)·min(-1)), although M VO2max was not overestimated in all the participants--it was underestimated in 30% of observations. Pearson's correlation, standard error of estimate (SEE), and total error (E) between measured and predicted VO2max were r = 0.646, 4.35, 4.08 ml·kg(-1)·min(-1) (P VO2max-All) and r = 0.642, 4.21, 3.98 ml·kg(-1)·min(-1) (P VO2max-2) indicating that the accuracy in prediction (error) was very similar whether using P VO2max-All or P VO2max-2, with up to 70% of the participants predicted scores within 1 SEE (～4 ml·kg(-1)·min(-1)) of M VO2max. In conclusion, the ACSM equation provides a reasonably good estimation of VO2max with no difference in predictive accuracy between P VO2max-2 and P VO2max-All, and hence, either approach may be equally useful in tracking an individual's aerobic fitness over time. However, if a precise knowledge of VO2max is required, then it is recommended that this be measured directly.     

The accuracy of the American College of Sports Medicine metabolic equation for walking at altitude and higher-grade conditions

The purpose of this study was to examine the accuracy of the American College of Sports Medicine (ACSM) walking equation at low walking speeds, altitude (1,550 m), and higher grades. Twenty men and women (mean +/- SD, age, 28 +/- 6 years; height, 171 +/- 13 cm; weight, 67.8 +/- 18.1 kg) completed 2 randomized testing sessions under altitude (AL) (P(I)o(2) = 123.1 mm Hg [20.93%]) and sea level control (SLC) (P(I)o(2) = 147.3 mm Hg [25.00%]) conditions. Steady-state oxygen uptake (Vo(2)) was measured while subjects walked at 50 m.min(-1) at 8 separate grades (0, 5, 10, 15, 18, 21, 24, and 27%). Steady-state Vo(2) measurements from the last 2 minutes of each grade in AL and SLC were compared to the predicted Vo(2) of each grade according to the ACSM walking equation. Mean Vo(2) differences between predicted and AL values ranged from -0.5 to 1.4 ml.kg(-1).min(-1), averaged -0.1 ml.kg(-1).min(-1) across all grades, and were significant (p < 0.05) at 0 percent grade. Mean Vo(2) differences between predicted and SLC values ranged from 0.6 to 3.0 ml.kg(-1).min(-1), averaged 1.4 ml.kg(-1).min(-1) across all grades, and were statistically significant (p < 0.05) at 0 and 5 percent. The standard error of the estimate (SEE) for the prediction of Vo(2) under AL and SLC were 2.2 and 2.0 ml.kg(-1).min(-1), respectively. Total errors for the prediction of Vo(2)max under AL and SLC were 2.3 and 2.6 ml.kg(-1).min(-1), respectively. Overall, the findings indicate that the current ACSM prediction equation for walking is appropriate for application at low speeds, moderate altitude, and higher grades.     

Preliminary findings on the influence of FTO rs9939609 and MC4R rs17782313 polymorphisms on resting energy expenditure,leptin and thyrotropin levels in obese non-morbid premenopausal women

Given that leptin, ghrelin and thyrotropin play a major role in the regulation of resting energy expenditure (REE) and that the FTO rs9939609 and the MC4R rs17782313 polymorphisms have been proposed to affect energy homeostasis, we hypothesized that both polymorphisms are associated with REE and that these relationships can be mediated by leptin, ghrelin and thyrotropin in obesity. Therefore, the present study aimed to examine the relationships between FTO rs9939609 and the MC4R rs17782313 with REE, leptin, ghrelin and thyrotropin levels in obese women. The study comprised 77 obese (body mass index 34.0?±?2.8 kg/m²) women (age 36.7?±?7 years). We measured body composition by dual-energy X-ray absorptiometry and REE by indirect calorimetry. We analysed fasting leptin, ghrelin and thyrotropin levels and the ratio of leptin to fat mass was calculated. Genotype distributions of the polymorphisms did not deviate from Hardy–Weinberg expectations (P values >0.2). Women carrying the A allele of the FTO rs9939609 had lower REE (1,580?±?22 vs. 1,739?±?35 kcal/day, P?<?0.001) and higher leptin to fat mass ratio (1.33?±?0.05 vs. 1.13?±?0.08 ng/ml kg, P?<?0.05) and thyrotropin levels (1.93?±?0.10 vs. 1.53?±?0.16 μU/ml, P?<?0.05) regardless of age and body mass index. We found no significant influence of the MC4R rs17782313 on energy metabolism or biochemical variables. Our findings confirm that the A allele of the FTO rs9939609 is associated with lower REE and increased plasma leptin levels. We also found an association between the FTO rs9939609 and thyrotropin, suggesting the possible influence of FTO in the hypothalamic–pituitary–thyroid axis as a potential mechanism of the increased adiposity.     

Effects of 12 weeks of aerobic exercise plus dietary restriction on body composition, resting energy expenditure and aerobic fitness in mildly obese middle-aged women

This study investigated the effects of 12 weeks of aerobic exercise plus voluntary food restriction on the body composition, resting metabolic rate (RMR) and aerobic fitness of mildly obese middle-aged women. The subjects were randomly assigned to exercise/diet (n = 17) or control (n = 15) groups. The exercise/diet group participated in an aerobic training programme, 45–60 min · day ^–1 at 50%–60% of maximal oxygen uptake (VO_2max), 3–4 days · week^–1, and also adopted a self-regulated energy deficit relative to predicted energy requirements (–1.05 MJ · day ^–1 to –1.14 MJ · day ^–1 ). After the regimen had been followed for 12 weeks, the body mass of the subjects had decreased by an average of 4.5 kg, due mainly to fat loss, with little change of fat free mass (m _ff). The absolute RMR did not change, but the experimental group showed significant increases in the RMR per unit of body mass (10%) and the RMR per unit of m _ff (4%). The increase in RMR/m _ff was not correlated with any increase in VO_2max/m _ff. The resting heat production per unit of essential body mass increased by an average of 21%, but the resting heat production rate per unit of fat tissue mass remained unchanged. We concluded that aerobic exercise enhances the effect of moderate dietary restriction by augmenting the metabolic activity of lean tissue.     

Characterization of the diurnal rhythm of peptide YY and its association with energy balance parameters in normal-weight premenopausal women

PYY may play a role in modulating satiety and energy expenditure; increasing PYY postprandially has been studied largely in single-meal responses. The diurnal rhythm of PYY and its role in energy balance have not been fully characterized. The purpose of our study was to characterize features of the diurnal rhythm of PYY and determine its role in regulating energy balance. This study was a cross-sectional analysis of 11 subjects in whom 24-h repeated blood sampling was conducted at baseline of a larger prospective study. Breakfast (B), lunch (L), dinner (D), and a snack (S) occurred between 0900 and 1900. Total PYY was assayed every hour from 0800 to 1000, every 20 min from 1000 to 2000, and every hour from 2000 to 0800. PYY variables included total AUC, postprandial peaks, and 24-h mean. Energy balance variables included energy intake, RMR, RQ, and NEAT. PYY postprandial peaks were significantly higher than fasting (P < 0.05). Twenty-four-hour peak PYY occurred after L and was significantly higher than all other peaks (P < 0.05). A cubic curve function accounted for most of the variance in PYY (r(2) = 69.9%, P < 0.01). Fasting PYY (0800) correlated with postprandial peaks at B (r = 0.77, P = 0.01), L (r = 0.71, P = 0.01), and D (r = 0.65, P = 0.03). The only significant association between PYY and energy expenditure was that RMR (kcal/24 h) correlated with 24-h mean PYY (r = 0.71, P = 0.013) and total AUC (r = 0.69, P = 0.019). We conclude that PYY displays a meal-driven diurnal rhythm and is correlated to RMR, a major contributor to energy expenditure. Thus, PYY varies in accordance with energy content and RMR, supporting a role for PYY in energy balance modulation.     

Effects of a comprehensive cardiac rehabilitation program on quality of life and exercise tolerance in women: A retrospective analysis

BACKGROUND: Currently, there are a lack of investigations that have examined the effect of participating in a comprehensive cardiac rehabilitation program on quality of life and physiological measures in women of different ages. The purpose of this investigation was to examine the effect of participating in a comprehensive cardiac rehabilitation program on quality of life, exercise tolerance, blood pressure and lipids in women between 33 and 82 years of age. METHODS: The 126 women participated in a 14-week cardiac rehabilitation program that consisted of 7 weeks of formal supervised exercise training and 7 weeks of unsupervised exercise and lifestyle modification. Physiologic and quality of life outcome measures obtained at the outset and after 14 weeks included: 1) exercise treadmill time; 2) resting and peak systolic and diastolic blood pressure; 3) total cholesterol, low-density lipoprotein cholesterol, high density lipoprotein cholesterol and Triglycerides; 4) Cardiac Quality of Life Index questionnaire. RESULTS: Significant improvements were found in the following quality of life measures after participating in the cardiac rehabilitation program: physical well being, psychosocial, worry, nutrition and symptoms. No significant differences were seen for any QOL variable between the different age groups. Significant improvements were seen in exercise tolerance (+21%) and high density lipoprotein (+5%). CONCLUSION: Cardiac rehabilitation may play an important role in improving quality of life, exercise tolerance and high density lipoprotein cholesterol levels in younger and older women with underlying cardiovascular disease.     

Low energy availability, not exercise stress, suppresses the diurnal rhythm of leptin in healthy young women

Because the effect of exercise on leptin was not established, we controlled energy intake (I) and exercise energy expenditure (E) to distinguish the independent effects of energy availability (A = I - E) and exercise stress (everything associated with exercise except its energy cost) on the diurnal leptin rhythm in healthy young women. In random order, we set A = 45 and 10 kcal. kg lean body mass(-1) (LBM) x day(-1) for 4 days during the early follicular phase of separate menstrual cycles in sedentary (S, n = 7) and exercising (X, n = 9: E = 30 kcal x kg LBM(-1) x day(-1)) women. Low energy availability suppressed the 24-h mean (P < 10(-6)) and amplitude (P < 10(-5)), whereas exercise stress did not (both P > 0.2). Suppressions of the 24-h mean (-72 +/- 3 vs. -53 +/- 3%, P < 0.001) and amplitude (-85 +/- 3 vs. -58 +/- 6%, P < 0.001) were more extreme in S vs. X than previously reported effects on luteinizing hormone pulsatility and carbohydrate availability. Thus the diurnal rhythm of leptin depends on energy, or carbohydrate, availability, not intake, and exercise has no suppressive effect on the diurnal rhythm of leptin beyond the impact of its energy cost on energy availability.     

A cross-cultural perspective on obesity and health in three groups of women: the Mississippi Choctaw, American Samoans, and African Americans

This study compares obesity as assessed by Body Mass Index (BMI) and the relationship of BMI to hypertension and diabetes in adult females from three populations, the Mississippi Band of Choctaw (N=50), American Samoa (N=155), and an African American community in West Alabama (N=367). These groups were surveyed in the early to mid 1990s. All three groups of women have very high levels of overweight and obesity, with the Samoans being most extreme in this regard. While there are indications that all three groups of women consume a calorically dense diet, low activity appears to be the most likely causal factor in the high rates of obesity. Relaxed negative attitudes toward an overweight/obese body image may also play a role in the high rates. The prevalences of hypertension and diabetes are alarmingly high in all three groups. There are, however, very different associations between BMI, hypertension, and diabetes in the three groups of women. The Samoans are substantially more obese (and older), but they have lower rates of hypertension than the African American women and lower rates of diabetes than the Choctaw women. While the genetic background of the three groups no doubt plays a role, it is also likely that a BMI of 30+, the common cutoff for obesity, means different things in these different populations. These results provide further support for the idea of variation in the relationship of BMI to disease in different populations.     

A seasonal difference of daily energy expenditure in a free-living subterranean rodent,the silvery mole-rat (Heliophobius argenteocinereus; Bathyergidae)

In seasonal climatic regimes, animals have to deal with changing environmental conditions. It is reasonable to expect that seasonal changes are reflected in animal overall energetics. The relation between daily energy expenditure (DEE) and seasonally variable ecological determinants has been studied in many free-living small mammals; however with inconsistent results. Subterranean mammals, i.e. fossorial (burrowing) mammals which live and forage underground, live in a seasonally and diurnally thermally stable environment and represent a suitable model to test seasonality in DEE in respect to seasonal changes, particularly those in soil characteristics and access to food supply. Both factors are affected by seasonal rainfall and are supposed to fundamentally determine activity of belowground dwellers. These ecological constraints are pronounced in some tropical regions, where two distinct periods, dry and rainy seasons, regularly alternate. To explore how a tropical mammal responds to an abrupt environmental change, we determined DEE, resting metabolic rate (RMR) and sustained metabolic scope (SusMS) in a solitary subterranean rodent, the silvery mole-rat, at the end of dry season and the onset of rainy season. Whereas RMR did not differ between both periods, mole-rats had 1.4 times higher DEE and SusMS after the first heavy rains. These findings suggest that rainfall is an important environmental factor responsible for higher energy expenditure in mole-rats, probably due to increased burrowing activity. SusMS in the silvery mole-rat is comparable to values in other bathyergids and all bathyergid values rank among the lowest SusMS found in endothermic vertebrates.     

Deletion of the RIIbeta-subunit of protein kinase A decreases body weight and increases energy expenditure in the obese, leptin-deficient ob/ob mouse

Disruption of the RIIbeta regulatory subunit of protein kinase A (PKA) results in mice with a lean phenotype, nocturnal hyperactivity, and increased resting metabolic rate. In this report, we have examined whether deletion of RIIbeta would lead to increased metabolism and rescue the obese phenotype of the leptin-deficient ob/ob (ob) mouse. Body weight gain and food consumption were decreased, whereas basal oxygen consumption and nocturnal locomotor activity were increased in the double mutant animals compared with ob mice. The ob mice are unable to maintain body temperature when placed in a cold environment due to a loss of brown adipose tissue activation, and this cold sensitivity was partially rescued by concomitant disruption of RIIbeta. These findings indicate that PKA modifies the phenotype of the leptin-deficient mouse, leading to increases in both thermogenesis and energy expenditure.     

Medical records for animals used in research, teaching, and testing: public statement from the American College of Laboratory Animal Medicine

Medical records are considered to be a key element of a program of adequate veterinary care for animals used in research, teaching, and testing. However, prior to the release of the public statement on medical records by the American College of Laboratory Animal Medicine (ACLAM), the guidance that was available on the form and content of medical records used for the research setting was not consistent and, in some cases, was considered to be too rigid. To address this concern, ACLAM convened an ad hoc Medical Records Committee and charged the Committee with the task of developing a medical record guideline that was based on both professional judgment and performance standards. The Committee provided ACLAM with a guidance document titled Public Statements: Medical Records for Animals Used in Research, Teaching, and Testing, which was approved by ACLAM in late 2004. The ACLAM public statement on medical records provides guidance on the definition and content of medical records, and clearly identifies the Attending Veterinarian as the individual who is charged with authority and responsibility for oversight of the institution's medical records program. The document offers latitude to institutions in the precise form and process used for medical records but identifies typical information to be included in such records. As a result, the ACLAM public statement on medical records provides practical yet flexible guidelines to assure that documentation of animal health is performed in research, teaching, and testing situations.     

A close call: the role of screening mammography in the fight against breast cancer: health and medicine for women: a multidisciplinary, evidence-based review of mid-life health concerns

A multidisciplinary panel debated the role of screening mammography in fighting breast cancer during the Health and Medicine for Women continuing medical education (CME) conference at Yale Medical School in September 2010. Different guidelines from professional societies have presented conflicting recommendations for patients regarding both the benefits of mammography and the appropriate age and frequency of screening. In addition, a recent longitudinal study argues that screening mammography may only offer a modest benefit in terms of reducing cancer mortality. In light of these considerations, the panel debated whether mammography should be an informed decision that must be discussed and individualized for each patient based on the context of risk factors such as family history, age, and genetic dispositions.