Physiological and Biomechanical Differences Between Seated and Standing Uphill Cycling

International Journal of Exercise Science 13(2): 996-1011, 2020. Despite differences in economy, cyclists climb in seated and standing positions. Prompted by gaps in research, we compared VO2 and heart rate (HR) (Study 1), muscle activation (Study 2) and breathing and pedaling entrainment (Study 3). METHODS: Subjects rode their bicycles on a treadmill in seated and standing positions. In Study 1, VO2 and HR of four male cyclists (21.3 ± 1.7 yrs; 69.1 ± 6 ml/kg/min) were collected, alternating positions every 5 minutes for 20 minutes (8 mph, 8% grade). In Study 2, muscle activations of eight male cyclists (24 ± 5 yrs, 67.6 ± 5.5 ml/kg/min) were collected on Rectus Femoris (RF), Biceps Femoris, Vastus Medialis (VM) and Gastrocnemius alternating positions every minute (8 mph, 8% grade). In Study 3, flow rate and entrainment of nine male cyclists (28 ± 7 yrs, 62.7 ± 7.7 ml/kg/min) were collected in 2-minute stages at 6, 8 and 10 mph, (8% grade) alternating positions every minute. RESULTS: VO2 and HR increased standing (3.17± 0.43 L/min, 175 ± 4 bpm) compared to seated (3.06 ± 0.37 L/min, 166 ± 5 bpm) (p \u3c 0.05). Normalized EMG for RF and VM increased standing (47 ± 5%, 57 ± 15%) compared to seated (34 ± 3%, 36 ± 8%) (p \u3c 0.05). Peak Inspiratory and Expiratory Flow increased standing (3.44±0.07 and 2.45±0.05 L/sec) compared to seated (3.09 ±0.06 and 2.21±0.04 L/sec) (p \u3c 0.05). CONCLUSION: Uphill cycling while standing results in decreased cycling economy due to physiological and biomechanical variations compared to riding seated

Predicting 6-Year Mortality Risk in Patients With Type 2 Diabetes

OBJECTIVE—The objective of this study was to create a tool that predicts the risk of mortality in patients with type 2 diabetes

Bisphenol A exposure and cardiac electrical conduction in excised rat hearts

BACKGROUND: Bisphenol A (BPA) is used to produce polycarbonate plastics and epoxy resins that are widely used in everyday products, such as food and beverage containers, toys and medical devices. Human biomonitoring studies have suggested that a large proportion of the population may be exposed to BPA. Recent epidemiological studies have reported correlations between increased BPA urinary concentrations and cardiovascular disease; yet the direct effects of BPA on the heart are unknown. OBJECTIVES: The goal of our studies was to measure BPA\u27s effect (0.1-100 μM) on cardiac impulse propagation ex vivo, using excised whole hearts from adult rats. METHODS: We measured atrial and ventricular activation times during sinus and paced rhythms using epicardial electrodes and optical mapping of transmembrane potential. Atrioventricular activation intervals and epicardial conduction velocities were computed using recorded activation times. RESULTS: Cardiac BPA exposure resulted in prolonged PR segment and decreased epicardial conduction velocity (0.1 - 100 μM), prolonged action potential duration (1 - 100 μM) and delayed atrioventricular conduction (10 - 100 μM). Importantly, these effects were observed after acute exposure (≤ 15 min), underscoring the potential detrimental effects of continuous BPA exposure. The highest BPA concentration used (100 μM) resulted in prolonged QRS intervals, dropped ventricular beats and eventually resulted in complete heart block. CONCLUSIONS: Our results show that acute BPA exposure slows electrical conduction in excised hearts from female rats. These findings emphasize the importance of examining BPA\u27s effect on heart electrophysiology and determining whether chronic in vivo exposure can cause/exacerbate conduction abnormalities in patients with pre-existing heart conditions and other high-risk populations

FGF21, a liver hormone that inhibits alcohol intake in mice, increases in human circulation after acute alcohol ingestion and sustained binge drinking at Oktoberfest

Objective: Excessive alcohol consumption is a leading cause of global morbidity and mortality. However, knowledge of the biological factors that influence ad libitum alcohol intake may be incomplete. Two large studies recently linked variants in the KLB locus with levels of alcohol intake in humans. KLB encodes β-klotho, co-receptor for the liver-derived hormone fibroblast growth factor 21 (FGF21). In mice, FGF21 reduces alcohol intake, and human Fgf21 variants are enriched among heavy drinkers. Thus, the liver may limit alcohol consumption by secreting FGF21. However, whether full-length, active plasma FGF21 (FGF21 (1–181)) levels in humans increase acutely or sub-chronically in response to alcohol ingestion is uncertain. Methods: We recruited 10 healthy, fasted male subjects to receive an oral water or alcohol bolus with concurrent blood sampling for FGF21 (1–181) measurement in plasma. In addition, we measured circulating FGF21 (1–181) levels, liver stiffness, triglyceride, and other metabolic parameters in three healthy Danish men before and after consuming an average of 22.6 beers/person/day (4.4 g/kg/day of ethanol) for three days during Oktoberfest 2017 in Munich, Germany. We further correlated fasting FGF21 (1–181) levels in 49 healthy, non-alcoholic subjects of mixed sex with self-reports of alcohol-related behaviors, emotional responses, and problems. Finally, we characterized the effect of recombinant human FGF21 injection on ad libitum alcohol intake in mice. Results: We show that alcohol ingestion (25.3 g or ∼2.5 standard drinks) acutely increases plasma levels of FGF21 (1–181) 3.4-fold in fasting humans. We also find that binge drinking for three days at Oktoberfest is associated with a 2.1-fold increase in baseline FGF21 (1–181) levels, in contrast to minor deteriorations in metabolic and hepatic biomarkers. However, basal FGF21 (1–181) levels were not correlated with differences in alcohol-related behaviors, emotional responses, or problems in our non-alcoholic subjects. Finally, we show that once-daily injection of recombinant human FGF21 reduces ad libitum alcohol intake by 21% in mice. Conclusions: FGF21 (1–181) is markedly increased in circulation by both acute and sub-chronic alcohol intake in humans, and reduces alcohol intake in mice. These observations are consistent with a role for FGF21 as an endocrine inhibitor of alcohol appetite in humans. Keywords: Fibroblast growth factor 21, FGF21, Alcohol, Alcohol appetit

Bodyweight Perceptions among Texas Women: The Effects of Religion, Race/Ethnicity, and Citizenship Status

Despite previous work exploring linkages between religious participation and health, little research has looked at the role of religion in affecting bodyweight perceptions. Using the theoretical model developed by Levin et al. (Sociol Q 36(1):157–173, 1995) on the multidimensionality of religious participation, we develop several hypotheses and test them by using data from the 2004 Survey of Texas Adults. We estimate multinomial logistic regression models to determine the relative risk of women perceiving themselves as overweight. Results indicate that religious attendance lowers risk of women perceiving themselves as very overweight. Citizenship status was an important factor for Latinas, with noncitizens being less likely to see themselves as overweight. We also test interaction effects between religion and race. Religious attendance and prayer have a moderating effect among Latina non-citizens so that among these women, attendance and prayer intensify perceptions of feeling less overweight when compared to their white counterparts. Among African American women, the effect of increased church attendance leads to perceptions of being overweight. Prayer is also a correlate of overweight perceptions but only among African American women. We close with a discussion that highlights key implications from our findings, note study limitations, and several promising avenues for future research

A cross-sectional study of vascular risk factors in a rural South African population : data from the Southern African Stroke Prevention Initiative (SASPI)

Background: Rural sub-Saharan Africa is at an early stage of economic and health transition. It is predicted that the 21st century will see a serious added economic burden from non-communicable disease including vascular disease in low-income countries as they progress through the transition. The stage of vascular disease in a population is thought to result from the prevalence of vascular risk factors. Already hypertension and stroke are common in adults in sub-Saharan Africa. Using a multidisciplinary approach we aimed to assess the prevalence of several vascular risk factors in Agincourt, a rural demographic surveillance site in South Africa. Methods: We performed a cross sectional random sample survey of adults aged over 35 in Agincourt (population ≈ 70 000). Participants were visited at home by a trained nurse who administered a questionnaire, carried out clinical measurements and took a blood sample. From this we assessed participants' history of vascular risk, blood pressure using an OMRON 705 CP monitor, waist circumference, body mass index (BMI), ankle brachial index (ABI), and total and HDL cholesterol. Results: 402 people (24% men) participated. There was a high prevalence of smoking in men, but the number of cigarettes smoked was small. There was a striking difference in mean BMI between men and women (22.8 kg/m2 versus 27.2 kg/m2), but levels of blood pressure were very similar. 43% of participants had a blood pressure greater than 140/90 or were on anti-hypertensive treatment and 37% of participants identified with measured high blood pressure were on pharmacological treatment. 12% of participants had an ABI of < 0.9, sugesting the presence of sub-clinical atheroma. 25.6% of participants had a total cholesterol level > 5 mmol/l. Conclusion: We found a high prevalence of hypertension, obesity in women, and a suggestion of subclinical atheroma despite relatively favourable cholesterol levels in a rural South African population. South Africa is facing the challenge of an emerging epidemic of vascular disease. Research to establish the social determinates of these risk factors and interventions to reduce both individual and population risk are required

Traditional Nonsteroidal Anti-Inflammatory Drugs and Postmenopausal Hormone Therapy: A Drug–Drug Interaction?

It is controversial whether estrogens confer cardioprotection. This study suggests that even should such a benefit exist, COX inhibitors may undermine cardioprotective effects of hormone therapy

Opposite Associations of Trunk and Leg Fat Depots with Plasma Ferritin Levels in Middle-Aged and Older Chinese Men and Women

Background: Few data have been published on the associations of ferritin with trunk and leg fat depots. We aimed to investigate these associations in a Chinese population. Methodology: Trunk fat mass and leg fat mass were determined in a cross-sectional sample of 1,150 Chinese (479 men and 671 women) aged 50–70 years by dual-energy X-ray absorptiometry scan. Fasting plasma ferritin was measured. Principal Findings: Plasma ferritin was positively correlated with waist circumference, waist-to-hip ratio, total body fat and trunk fat mass, but inversely correlated with leg fat mass in men (r = 0.16, 0.26, 0.19, 0.22 and 20.12, respectively, all P,0.05) and women (r = 0.16, 0.16, 0.08, 0.17 and 20.12, respectively, all P,0.05). Multivariate regression analysis showed that ferritin levels increased with larger trunk fat mass (b = 0.33 6 0.08 for men and b = 0.21 6 0.05 for women, both P,0.001) while decreased with larger leg fat mass (b = 20.12 6 0.09, P = 0.15 for men; and b = 20.14 6 0.05, P = 0.005 for women). Moreover, plasma ferritin levels decreased with increasing tertile of leg fat mass among each tertile of trunk fat mass. Conclusion: This is the first study to report the opposite associations of trunk and leg fat depots with plasma ferritin levels

Does owning a pet protect older people against loneliness?

This article has been made available through the Brunel Open Access Publishing Fund.Pet ownership is thought to make a positive contribution to health, health behaviours and the general well-being of older people. More specifically pet ownership is often proposed as a solution to the problem of loneliness in later life and specific 'pet based' interventions have been developed to combat loneliness. However the evidence to support this relationship is slim and it is assumed that pet ownership is a protection against loneliness rather than a response to loneliness. The aim of this paper is to examine the association between pet ownership and loneliness by exploring if pet ownership is a response to, or protection against, loneliness using Waves 0-5 from the English Longitudinal Study of Ageing (ELSA)