Determinants of sleep quality in 5835 individuals living with and beyond breast, prostate, and colorectal cancer: a cross-sectional survey

Purpose: The present study aimed to quantify the level of sleep problems in 5835 breast, prostate, and colorectal cancer survivors, and explore a number of potential determinants of poor sleep quality in the present sample. BMI, diet, and physical activity were of particular interest as potential determinants. / Methods: Participants who completed the ‘Health and Lifestyle after Cancer’ survey were adults who had been diagnosed with breast, prostate, or colorectal cancer (mean time since cancer diagnosis was 35.5 months, SD=13.56). Sleep quality was assessed using the Pittsburgh Sleep Quality Index. BMI was calculated from self-reported height and weight. Participants were categorised as meeting/not meeting the World Cancer Research Fund (WCRF) recommendations for fibre, fruit and vegetables, added sugar, red meat, processed meat, fat, alcohol, and physical activity. Analyses accounted for demographic and clinical factors. / Results: Fifty-seven percent of those with sleep data were classified as poor sleepers (response rate 79%). Being female, having a higher number of cancer treatments, more comorbid conditions, and being more anxious/depressed increased the odds of being a poor sleeper. After adjustment for these factors, there were no associations between diet/alcohol/physical activity and sleep. However, BMI was associated with sleep. Individuals in the overweight and obese categories had 22% and 79% higher odds of being poor sleepers than individuals in the underweight/healthy weight category, respectively. / Conclusions: The findings suggest that there may be a need to develop sleep quality interventions for cancer survivors with obesity. Even after adjustment for multiple clinical and demographic factors, BMI (particularly obesity) was associated with poor sleep. Thus, researchers and health professionals should find ways to support individuals with overweight and obesity to improve their sleep quality

Attenuated Fatigue in Slow Twitch Skeletal Muscle during Isotonic Exercise in Rats with Chronic Heart Failure

During isometric contractions, slow twitch soleus muscles (SOL) from rats with chronic heart failure (chf) are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic) contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf) if left ventricle end diastolic pressure was >15mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off) at 30Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (Fmax) and the concentrations of ATP and CrP were not different in the two groups. During stimulation, Fmax and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue

Changes in Intracellular Na+ following Enhancement of Late Na+ Current in Virtual Human Ventricular Myocytes

The slowly inactivating or late Na+ current, INa-L, can contribute to the initiation of both atrial and ventricular rhythm disturbances in the human heart. However, the cellular and molecular mechanisms that underlie these pro-arrhythmic influences are not fully understood. At present, the major working hypothesis is that the Na+ influx corresponding to I(Na-L)significantly increases intracellular Na+, [Na]; and the resulting reduction in the electrochemical driving force for Na+ reduces and (may reverse) Na+/Ca2+ exchange. These changes increase intracellular Ca2+, [Ca2+]; which may further enhance I(Na-L)due to calmodulindependent phosphorylation of the Na+ channels. This paper is based on mathematical simulations using the O'Hara et al (2011) model of baseline or healthy human ventricular action potential waveforms(s) and its [Ca2(+)]; homeostasis mechanisms. Somewhat surprisingly, our results reveal only very small changes (<= 1.5 mM) in [Na] even when INa-L is increased 5-fold and steady-state stimulation rate is approximately 2 times the normal human heart rate (i.e. 2 Hz). Previous work done using well-established models of the rabbit and human ventricular action potential in heart failure settings also reported little or no change in [Na] when I(Na-L)was increased. Based on our simulations, the major short-term effect of markedly augmenting I(Na-L)is a significant prolongation of the action potential and an associated increase in the likelihood of reactivation of the L-type Ca2+ current, Ica-L. Furthermore, this action potential prolongation does not contribute to [Na]; increase.This work was supported by (i) the "VI Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica" from the Ministerio de Economia y Competitividad of Spain (grant number TIN2012-37546-C03-01) and the European Commission (European Regional Development Funds-ERDF-FEDER), (ii) by the Direccion General de Politica Cientifica de la Generalitat Valenciana (grant number GV/2013/119), and by (iii), Programa Prometeo (PROMETEO/2016/088) de la Conselleria d'Educacio Formacio I Ocupacio, Generalitat Valenciana. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.K Cardona; Trénor Gomis, BA.; W Giles (2016). Changes in Intracellular Na+ following Enhancement of Late Na+ Current in Virtual Human Ventricular Myocytes. PLoS ONE. 11(11). https://doi.org/10.1371/journal.pone.0167060S111

Determinants of sleep quality in 5835 individuals living with and beyond breast, prostate, and colorectal cancer: a cross-sectional survey

Purpose The present study aimed to quantify the level of sleep problems in 5835 breast, prostate, and colorectal cancer survivors, and explore a number of potential determinants of poor sleep quality in the present sample. BMI, diet, and physical activity were of particular interest as potential determinants. Methods Participants who completed the ‘Health and Lifestyle after Cancer’ survey were adults who had been diagnosed with breast, prostate, or colorectal cancer (mean time since cancer diagnosis was 35.5 months, SD=13.56). Sleep quality was assessed using the Pittsburgh Sleep Quality Index. BMI was calculated from self-reported height and weight. Participants were categorised as meeting/not meeting the World Cancer Research Fund (WCRF) recommendations for fibre, fruit and vegetables, added sugar, red meat, processed meat, fat, alcohol, and physical activity. Analyses accounted for demographic and clinical factors. Results Fifty-seven percent of those with sleep data were classified as poor sleepers (response rate 79%). Being female, having a higher number of cancer treatments, more comorbid conditions, and being more anxious/depressed increased the odds of being a poor sleeper. After adjustment for these factors, there were no associations between diet/alcohol/physical activity and sleep. However, BMI was associated with sleep. Individuals in the overweight and obese categories had 22% and 79% higher odds of being poor sleepers than individuals in the underweight/healthy weight category, respectively. Conclusions The findings suggest that there may be a need to develop sleep quality interventions for cancer survivors with obesity. Even after adjustment for multiple clinical and demographic factors, BMI (particularly obesity) was associated with poor sleep. Thus, researchers and health professionals should find ways to support individuals with overweight and obesity to improve their sleep quality. Implications for Cancer Survivors The present findings highlight that poor sleep is a common issue in cancer survivors. Interventions seeking to improve outcomes for cancer survivors over the longer term should consider sleep quality