Comparing continuous and intermittent exercise. An "isoeffort" and "isotime" approach

The present study proposes an alternative way of comparing performance and acute physiological responses to continuous exercise with those of intermittent exercise, ensuring similar between-protocol overall effort (isoeffort) and the same total duration of exercise (isotime). This approach was expected to overcome some drawbacks of traditional methods of comparison. Fourteen competitive cyclists (20±3 yrs) performed a preliminary incremental test and four experimental 30-min self-paced protocols, i.e. one continuous and three passive-recovery intermittent exercise protocols with different workto- rest ratios (2 = 40:20s, 1 = 30:30s and 0.5 = 20:40s). A "maximal session effort" prescription was adopted for this experimental design. As expected, a robust perceived exertion template was observed irrespective of exercise protocol. Similar between-protocol pacing strategies further support the use of the proposed approach in competitive cyclists. Total work, oxygen uptake and heart rate mean values were significantly higher (P<0.05) in the continuous compared to intermittent protocols, while lactate values were lower. Manipulating the work-to-rest ratio in intermittent exercise, total work, oxygen uptake and heart rate mean values decreased with the decrease in the work-to-rest ratio, while lactate values increased. Despite this complex physiological picture, all protocols showed similar ventilatory responses and a nearly perfect relationship between respiratory frequency and perceived exertion. In conclusion, our data indicate that overall effort and total duration of exercise are two critical parameters that should both be controlled when comparing continuous with intermittent exercise. On an isoeffort and isotime basis, the work-to-rest ratio manipulation affects physiological responses in a different way from what has been reported in literature with traditional methods of comparison. Finally, our data suggest that during intermittent exercise respiratory frequency reflects physiological strain better than oxygen uptake, heart rate and blood lactate

Rationale for the use of metformin and exercise to counteract statin-associated side effects

Introduction: Statins are the most widely prescribed drugs for lowering low-density lipoprotein cholesterol (LDL-C) and reducing cardiovascular morbidity and mortality. They are usually well-tolerated, but have two main safety concerns: statin-associated muscle symptoms (SAMS) and new-onset type 2 diabetes (NOD). Methods: A PubMed search was carried out using the following key words were used: statins, statin-associated muscle symptoms, statin myalgia, statin-associated diabetes, metformin and statins, exercise and statins. Results: Mitochondrial damage and muscle atrophy are likely the central mechanisms producing SAMS, whereas decreased glucose transport, fatty acid oxidation and insulin secretion are likely involved in the development of NOD. Metformin and exercise training share many pathways that could potentially contrast SAMS and NOD. Clinical evidence also supports the combination of statins with metformin and exercise. Conclusion: This combination appears attractive both from a clinical and an economical viewpoint, since all three therapies are highly cost-effective and their combination could result in diabetes and cardiovascular disease prevention

Acute Pancreatitis After a Meatless Burger in Familial Chylomicronemia Syndrome

A 62-year-old woman with familial chylomicronemia syndrome (FCS) resulting from documented lipoprotein lipase deficiency presented with pancreatitis 48 hours after eating a plant-based burger with tomato and lettuce at a local restaurant. She had not previously eaten such a burger. She was diagnosed with FCS at age 12 after experiencing chronic pancreatitis since age 4. At this presentation her triglyceride levels were 1493 mg/dL and her lipase was 510 U/L (normal range 13-60). An abdominal computed tomography (CT) scan confirmed acute pancreatitis

Nationale cultuur en de wereldwijde verspreiding van corporate governancecodes

Hoe komen corporate governancecodes tot stand? Er is niet zoiets als een universele corporate governancecode. Alom wordt het idee gedeeld dat de Angelsaksische praktijk de belangrijkste bron is bij de verspreiding van deze codes. Maar dat betekent niet dat de ‘Britse bron’ klakkeloos wordt gekopieerd. Toch tonen codes wereldwijd opvallende overeenkomsten wat betreft de doelstellingen van corporate governance. Welke dynamiek speelt dus een rol bij de totstandkoming van al die afwijkende codes? Een analyse, gebaseerd op het proefschrift ‘Institutional contextuality of business best practices. The persistent cross-national diversity in the creation of corporate governance codes.

Coronary artery disease with normal lipids and low coronary artery calcium in two women with high lipoprotein(a)

We present 2 patients with elevated levels of lipoprotein (a) and significant coronary artery disease despite having little coronary artery calcification. Clinicians should be aware that patients with elevated lipoprotein (a) may have important coronary artery disease with low coronary artery calcification scores

Renal protection with glucagon-like peptide-1 receptor agonists

There is an unmet need for renoprotective drugs for more pronounced reduction of albuminuria beyond that provided by renin-angiotensin system (RAS) blockers and for effective slowdown of eGFR decline independent of albuminuria. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have proven effective in reducing prespecified secondary composite kidney outcomes in cardiovascular outcome trials. However, GLP-1 RAs showed a prevailing anti-albuminuric effect, additional to that of RAS blockers, and a non-significant risk reduction in worsening of kidney function, at variance with sodium-glucose cotransporter 2 inhibitors. Mechanisms underlying renal protection with GLP-1 RAs are porly understood. Though treatment with GLP-1 RAs resulted in better glycaemic, blood pressure and body weight control versus placebo, correction for on-trial changes in these parameters did not significantly affect results. Anti-inflammatory/anti-oxidant effects via intracellular signalling through protein kinase A, natriuretic effect via inhibition of sodium-hydrogen exchanger 3 and reduction of hyperfiltration have been proposed as direct renoprotective effects

Timely exercise for controlling glucose and oxidative stress. Reply to Chacko E. [letter]

We agree with Dr. Chacko that exercising between the first and the second meal of the day has a different effect on postprandial events compared to when the exercise is performed before or just after breakfast. In fact, the so-called second-meal phenomenon, first described at the beginning of the nineteenth century, shows that postprandial glycaemic response to lunch is influenced by previous breakfast consumption, which appears to be preserved in type 2 diabetic patients

Exercising for metabolic control. Is timing important?

Atherosclerosis-related cardiovascular disease and diabetes mellitus are leading causes of mortality in the world and both disorders are closely related to the postprandial phenomena. Regular exercise is being strongly advocated as a precious tool in easing the global burden of chronic disease. Although exercise intensity, duration and frequency are well established in current guidelines for healthy and diabetic individuals, there is still no consensus on the optimal timing of exercise in relation to the last meal. The present paper reviews the existing literature on the 'when?' of aerobic exercise for metabolic control in healthy and diabetic individuals. Effective control of postprandial phenomena might prove to be a useful tool in the prevention of chronic disease. Exercise appears to influence glycemic and triglyceridemic responses differently depending on the meal composition and time lapse from meals. In healthy individuals, fasted-state exercise favors postprandial triglyceridemic control and the insulin sensitivity related to it. However, there is a lack of data on this matter in diabetic patients. On the other hand, when postprandial glycemia is of concern, aerobic exercise works better when performed after a meal, both in healthy and in diabetic patients