Carbohydrate Mouth Rinsing Does Not Alter Central or Peripheral Fatigue After High-Intensity and Low-Intensity Exercise in Men

Whether sympathetic activity influences cerebral blood flow (CBF) and oxygenation remains controversial. The influence of sympathetic activity on CBF and oxygenation was evaluated by the effect of phenylephrine on middle cerebral artery (MCA) mean flow velocity ( Vmean) and the near-infrared spectroscopy-derived frontal lobe oxygenation (ScO2) at rest and during exercise. At rest, nine healthy male subjects received bolus injections of phenylephrine (0.1, 0.25, and 0.4 mg), and changes in mean arterial pressure (MAP), MCA Vmean, internal jugular venous O2 saturation (SjvO2), ScO2, and arterial Pco2 (PaCO2) were measured and the cerebral metabolic rate for O2 (CMRO2) was calculated. In randomized order, a bolus of saline or 0.3 mg of phenylephrine was then injected during semisupine cycling, eliciting a low (∼110 beats/min) or a high (∼150 beats/min) heart rate. At rest, MAP and MCA Vmean increased ∼20% ( P < 0.001) and ∼10% ( P < 0.001 for 0.25 mg of phenylephrine and P < 0.05 for 0.4 mg of phenylephrine), respectively. ScO2 then decreased ∼7% ( P < 0.001). Phenylephrine had no effect on SjvO2, PaCO2, or CMRO2. MAP increased after the administration of phenylephrine during low-intensity exercise (∼15%), but this was attenuated (∼10%) during high-intensity exercise ( P < 0.001). The reduction in ScO2 after administration of phenylephrine was attenuated during low-intensity exercise (−5%, P < 0.001) and abolished during high-intensity exercise (−3%, P = not significant), where PaCO2 decreased 7% ( P < 0.05) and CMRO2 increased 17% ( P < 0.05). These results suggest that the administration of phenylephrine reduced ScO2 but that the increased cerebral metabolism needed for moderately intense exercise eliminated that effect.

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Psychological distress and its associated risk factors among university students

Revista da Associação Médica Brasileira ◽

10.1590/1806-9282.66.4.414 ◽

2020 ◽

Vol 66 (4) ◽

pp. 414-418

Author(s):

Tingting Li ◽

Xu Zhang ◽

Mingming Chen ◽

Rui Wang ◽

Lianping He ◽

...

Keyword(s):

Risk Factors ◽

Psychological Distress ◽

University Students ◽

High Intensity ◽

Education Level ◽

High Intensity Exercise ◽

Low Intensity ◽

Significant Difference ◽

Associated Risk Factors ◽

Low Intensity Exercise

SUMMARY OBJECTIVE Psychological distress is an important mental health problem among university students. The goal of this study was to determine psychological distress and its associated risk factors among students in the Anhui province. METHODS A cross-sectional study was conducted in a sample of 1304 students. In this study, a self-administered questionnaire consisting of the general demography and General Health Questionnaire (GHQ-12) was completed. Psychological distress was assessed using the GHQ-12-item questionnaire. A dichotomous category split was imposed on the GHQ-12 for the purpose of analysis. A GHQ-12 score of 4 or higher indicated psychological distress. The data were analyzed by SPSS 20.0 system. RESULTS A total of 1304 samples were analyzed in this study. The results indicated that the education level of the father and mother was associated with the students’ psychological distress (P<0.001). A significant association was found between high-intensity exercise and low-intensity exercise and psychological distress. However, no significant difference was identified between gender and psychological distress (P=0.173). CONCLUSION The education level of parents, high-intensity exercise, and low-intensity exercise were associated with psychological distress. Our results suggest that it is indispensable to raise awareness of psychological disorders and its associated risk factors among university students. Further studies are required to develop appropriate interventions for high-risk groups.

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Defining the contribution of skeletal muscle pyruvate dehydrogenase α1 to exercise performance and insulin action

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00241.2018 ◽

2018 ◽

Vol 315 (5) ◽

pp. E1034-E1045 ◽

Cited By ~ 6

Author(s):

Kristoffer Svensson ◽

Jessica R. Dent ◽

Shahriar Tahvilian ◽

Vitor F. Martins ◽

Abha Sathe ◽

...

Keyword(s):

Skeletal Muscle ◽

Insulin Sensitivity ◽

Energy Expenditure ◽

Exercise Performance ◽

Pyruvate Dehydrogenase ◽

High Intensity ◽

High Intensity Exercise ◽

Low Intensity ◽

Low Intensity Exercise ◽

Muscle Contractile

The pyruvate dehydrogenase complex (PDC) converts pyruvate to acetyl-CoA and is an important control point for carbohydrate (CHO) oxidation. However, the importance of the PDC and CHO oxidation to muscle metabolism and exercise performance, particularly during prolonged or high-intensity exercise, has not been fully defined especially in mature skeletal muscle. To this end, we determined whether skeletal muscle-specific loss of pyruvate dehydrogenase alpha 1 ( Pdha1), which is a critical subunit of the PDC, impacts resting energy metabolism, exercise performance, or metabolic adaptation to high-fat diet (HFD) feeding. For this, we generated a tamoxifen (TMX)-inducible Pdha1 knockout (PDHmKO) mouse, in which PDC activity is temporally and specifically ablated in adult skeletal muscle. We assessed energy expenditure, ex vivo muscle contractile performance, and endurance exercise capacity in PDHmKO mice and wild-type (WT) littermates. Additionally, we studied glucose homeostasis and insulin sensitivity in muscle after 12 wk of HFD feeding. TMX administration largely ablated PDHα in skeletal muscle of adult PDHmKO mice but did not impact energy expenditure, muscle contractile function, or low-intensity exercise performance. Additionally, there were no differences in muscle insulin sensitivity or body composition in PDHmKO mice fed a control or HFD, as compared with WT mice. However, exercise capacity during high-intensity exercise was severely impaired in PDHmKO mice, in parallel with a large increase in plasma lactate concentration. In conclusion, although skeletal muscle PDC is not a major contributor to resting energy expenditure or long-duration, low-intensity exercise performance, it is necessary for optimal performance during high-intensity exercise.

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Acute Exercise Modulates Feature-selective Responses in Human Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01082 ◽

2017 ◽

Vol 29 (4) ◽

pp. 605-618 ◽

Cited By ~ 14

Author(s):

Tom Bullock ◽

James C. Elliott ◽

John T. Serences ◽

Barry Giesbrecht

Keyword(s):

High Intensity ◽

Acute Exercise ◽

Tuning Curve ◽

Brain Activity ◽

Human Vision ◽

Sensory Cortex ◽

Orientation Discrimination ◽

Active Movement ◽

Low Intensity ◽

Low Intensity Exercise

An organism's current behavioral state influences ongoing brain activity. Nonhuman mammalian and invertebrate brains exhibit large increases in the gain of feature-selective neural responses in sensory cortex during locomotion, suggesting that the visual system becomes more sensitive when actively exploring the environment. This raises the possibility that human vision is also more sensitive during active movement. To investigate this possibility, we used an inverted encoding model technique to estimate feature-selective neural response profiles from EEG data acquired from participants performing an orientation discrimination task. Participants (n = 18) fixated at the center of a flickering (15 Hz) circular grating presented at one of nine different orientations and monitored for a brief shift in orientation that occurred on every trial. Participants completed the task while seated on a stationary exercise bike at rest and during low- and high-intensity cycling. We found evidence for inverted-U effects; such that the peak of the reconstructed feature-selective tuning profiles was highest during low-intensity exercise compared with those estimated during rest and high-intensity exercise. When modeled, these effects were driven by changes in the gain of the tuning curve and in the profile bandwidth during low-intensity exercise relative to rest. Thus, despite profound differences in visual pathways across species, these data show that sensitivity in human visual cortex is also enhanced during locomotive behavior. Our results reveal the nature of exercise-induced gain on feature-selective coding in human sensory cortex and provide valuable evidence linking the neural mechanisms of behavior state across species.

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Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans

Yearbook of Sports Medicine ◽

10.1016/s0162-0908(09)79591-1 ◽

2010 ◽

Vol 2010 ◽

pp. 172-174

Author(s):

R.J. Shephard

Keyword(s):

High Intensity ◽

High Intensity Exercise ◽

Dietary Nitrate ◽

Low Intensity ◽

Nitrate Supplementation ◽

Low Intensity Exercise ◽

Exercise In Humans

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High-Intensity Exercise Causes Greater Irisin Response Compared with Low-Intensity Exercise under Similar Energy Consumption

The Tohoku Journal of Experimental Medicine ◽

10.1620/tjem.233.135 ◽

2014 ◽

Vol 233 (2) ◽

pp. 135-140 ◽

Cited By ~ 59

Author(s):

Yoshifumi Tsuchiya ◽

Daisuke Ando ◽

Kazushige Goto ◽

Masataka Kiuchi ◽

Mitsuya Yamakita ◽

...

Keyword(s):

Energy Consumption ◽

High Intensity ◽

High Intensity Exercise ◽

Low Intensity ◽

Low Intensity Exercise

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Low-intensity exercise training decreases cardiac output and hypertension in spontaneously hypertensive rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.273.6.h2627 ◽

1997 ◽

Vol 273 (6) ◽

pp. H2627-H2631 ◽

Cited By ~ 30

Author(s):

Acácio Salvador Véras-Silva ◽

Katt Coelho Mattos ◽

Nilo Sérgio Gava ◽

Patricia Chakur Brum ◽

Carlos Eduardo Negrão ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Cardiac Output ◽

Exercise Training ◽

High Intensity ◽

Peripheral Resistance ◽

High Intensity Exercise ◽

Spontaneously Hypertensive ◽

Low Intensity ◽

Low Intensity Exercise

The decrease in cardiac sympathetic tone and heart rate after low-intensity exercise training may have hemodynamic consequences in spontaneously hypertensive rats (SHR). The effects of exercise training of low and high intensity on resting blood pressure, cardiac output, and total peripheral resistance were studied in sedentary ( n = 17), low- ( n = 17), and high-intensity exercise-trained ( n = 17) SHR. Exercise training was performed on a treadmill for 60 min, 5 times per week for 18 weeks, at 55% or 85% maximum oxygen uptake. Blood pressure was evaluated by a cannula inserted into the carotid artery, and cardiac output was evaluated by a microprobe placed around the ascending aorta. Low-intensity exercise-trained rats had a significantly lower mean blood pressure than sedentary and high-intensity exercise-trained rats (160 ± 4 vs. 175 ± 3 and 173 ± 2 mmHg, respectively). Cardiac index (20 ± 1 vs. 24 ± 1 and 24 ± 1 ml ⋅ min−1 ⋅ 100 g−1, respectively) and heart rate (332 ± 6 vs. 372 ± 14 and 345 ± 9 beats/min, respectively) were significantly lower in low-intensity exercise-trained rats than in sedentary and high-intensity exercise-trained rats. No significant difference was observed in stroke volume index and total peripheral resistance index in all groups studied. In conclusion, low-intensity, but not high-intensity, exercise training decreases heart rate and cardiac output and, consequently, attenuates hypertension in SHR.

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Exercise Intensity and the Thermic EfiWif of Food

International Journal of Sport Nutrition ◽

10.1123/ijsn.2.1.87 ◽

1992 ◽

Vol 2 (1) ◽

pp. 87-95 ◽

Cited By ~ 6

Author(s):

Kent W. Goben ◽

Gary A. Sforzo ◽

Patricia A. Frye

Keyword(s):

Exercise Intensity ◽

High Intensity ◽

Treadmill Exercise ◽

Liquid Meal ◽

Low Intensity ◽

Thermic Effect Of Food ◽

Effect Of Food ◽

Low Intensity Exercise ◽

Male Subjects ◽

Thermic Effect

This study investigated the effect of varying exercise intensity on the thermic effect of food (TEF). Sixteen lean male subjects were matched forand randomly assigned to either a high or low intensity group for 30 min of treadmill exercise. Caloric expenditure was measured using indirect calorimetry at rest and at 30-min intervals OYer 3 hrs following each of three conditions: a 750-kcal liquid meal, high or low intensity exercise, and a 750-kcal liquid meal followed by high or low intensity exercise. Low intensity exercise enhanced the TEF during recovery at 60 and 90 min while high intensity enhanced it only at 180 min but depressed it at 30 min. Total metabolic expense for a 3-hr postmeal period was not differently affected by the two exercise intensities. Exercise following a meal had a synergistic effect on metabolism; however, this effect was delayed until 180 min postmeal when exercise intensity was high. The circulatory demands of high intensity exercise may have initially blunted the TEF, but ultimately the TEF measured over the 3-hr period was at least equal to that experienced following low intensity exercise.

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The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2016-0581 ◽

2017 ◽

Vol 42 (9) ◽

pp. 986-993 ◽

Cited By ~ 5

Author(s):

Laurel A. Littlefield ◽

Zacharias Papadakis ◽

Katie M. Rogers ◽

José Moncada-Jiménez ◽

J. Kyle Taylor ◽

...

Keyword(s):

Oxygen Consumption ◽

Energy Expenditure ◽

Oxygen Uptake ◽

Test Meal ◽

High Intensity ◽

Postprandial Lipemia ◽

High Intensity Exercise ◽

Low Intensity ◽

Low Intensity Exercise ◽

Excess Postexercise Oxygen Consumption

Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg−1·min−1; body mass index, 31.8 ± 4.5 kg/m2) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%–50% oxygen uptake reserve (LI), high-intensity exercise at 70%–80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control (p < 0.05) with no differences between the exercise conditions (p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men.

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Exercise Intensities as Factors of Metabolic Outcomes in Type 2 Diabetes: A Systematic Review

Home Health Care Management & Practice ◽

10.1177/1084822318815446 ◽

2018 ◽

Vol 31 (3) ◽

pp. 193-203

Author(s):

Elizabeth Moxley ◽

Tory Bugaieski

Keyword(s):

Type 2 Diabetes ◽

High Intensity ◽

Fasting Glucose ◽

High Intensity Exercise ◽

Systemic Review ◽

Moderate Intensity ◽

Low Intensity ◽

Metabolic Outcomes ◽

Low Intensity Exercise

Exercise is effective to prevent and treat type 2 diabetes, although currently underutilized. This review analyzes the metabolic response to exercise performance at various intensities in individuals with type 2 diabetes. These findings provide insight into the development of safe and efficacious exercise prescriptions and education. We conducted a systemic review of the literature to examine the association of various exercise protocols with metabolic outcomes in type 2 diabetes. Between 1984 and 2018, 29 studies were categorized per exercise mode and intensity levels according to the American College of Sports Medicine standards. The most consistent improvement was found in HbA1c following moderate- to high-intensity exercise—post-exercise fasting glucose improved to a lesser extent. Low-intensity exercise improved HOMA-IR (homeostasis model assessment for insulin resistance) levels. Glucose and HbA1c improved most following interval compared with continuous exercise, irrespective of intensity. A comparison of high-intensity exercise with moderate-intensity exercise demonstrated few differences in HbA1c, fasting glucose, fasting insulin, and HOMA-IR. Irrespective of exercise intensity, HbA1c improvements were observed, suggesting a delayed progression to diabetes-related complications. Initial low-intensity exercise, with increased quantities when feasible, will contribute to metabolic improvements. The variability in methodology and measurement contributed to inconsistent outcomes; additional research with larger samples sizes is warranted.

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