Martin R. Lindley

The anti-inflammatory effects of exercise: mechanisms and implications for the prevention and treatment of disease

Regular exercise reduces the risk of chronic metabolic and cardiorespiratory diseases, in part because exercise exerts anti-inflammatory effects. However, these effects are also likely to be responsible for the suppressed immunity that makes elite athletes more susceptible to infections. The anti-inflammatory effects of regular exercise may be mediated via both a reduction in visceral fat mass (with a subsequent decreased release of adipokines) and the induction of an anti-inflammatory environment with each bout of exercise. In this Review, we focus on the known mechanisms by which exercise — both acute and chronic — exerts its anti-inflammatory effects, and we discuss the implications of these effects for the prevention and treatment of disease.

Eicosapentaenoic acid is more effective than docosahexaenoic acid in inhibiting proinflammatory mediator production and transcription from LPS-induced human asthmatic alveolar macrophage cells

BACKGROUND & AIMS The purpose of the study was to determine which of the active constituents of fish oil, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), is most effective in suppressing proinflammatory mediator generation and cytokine expression from LPS-stimulated human asthmatic alveolar macrophages (AMphi). METHODS The AMphi were obtained from twenty-one asthmatic adults using fiberoptic bronchoscopy. Cells were pretreated with DMEM, pure EPA, an EPA-rich media (45% EPA/10% DHA), pure DHA, a DHA-rich media (10% EPA/50% DHA) or Lipovenos (n-6 PUFA), and then exposed to Dulbeccos Modified Eagles Medium (DMEM) (-) or LPS (+). Supernatants were analyzed for leukotriene (LT)B(4), prostaglandin (PG)D(2), tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta production. Detection of TNF-alpha and IL-1beta mRNA expression levels was quantified by reverse transcriptase polymerase chain reaction. RESULTS 120 microM pure EPA and EPA-rich media significantly (p<0.05) suppressed TNF-alpha and IL-1beta mRNA expression and the production of LTB(4), PGD(2) and TNF-alpha and IL-1beta in LPS-stimulated primary AMphi cells obtained from asthmatic patients to a much greater extent than 120 microM pure DHA and DHA-rich media respectively. CONCLUSIONS This study has shown for the first time that EPA is a more potent inhibitor than DHA of inflammatory responses in human asthmatic AMphi cells.

Effect of inspiratory muscle training on exercise tolerance in asthmatic individuals.

PURPOSE The aim of this study was to determine the effects of inspiratory muscle training (IMT) on exercise tolerance, inspiratory muscle fatigue, and the perception of dyspnea in asthmatic individuals. METHODS Using a matched double-blind placebo-controlled design, 15 clinically diagnosed asthmatic individuals underwent either 6 wk of IMT (n = 7) consisting of 30 breaths twice daily at 50% maximum inspiratory pressure (PI max) or sham-IMT (placebo; PLA, n = 8) consisting of 60 breaths daily at 15% PI max. Time to the limit of exercise tolerance (Tlim) was assessed using constant-power output (70% peak power) cycle ergometry. Inspiratory muscle fatigue was determined by comparing the pre- to postexercise reduction in PI max. Dyspnea during the Tlim test was evaluated at 2-min intervals using the Borg CR-10 scale. RESULTS There were no significant changes (P > 0.05) in Tlim, inspiratory muscle fatigue, or perception of dyspnea in the PLA group after the intervention. In contrast, in the IMT group, PI max increased by 28%, and Tlim increased by 16% (P < 0.05). Dyspnea during exercise was also reduced significantly by 16% (P < 0.05). The exercise-induced fall in PI max was reduced from 10% before IMT to 6% after IMT (P < 0.05), despite the longer Tlim. Pulmonary function remained unchanged in both the IMT and PLA groups. CONCLUSIONS These data suggest that IMT attenuates inspiratory muscle fatigue, reduces the perception of dyspnea, and increases exercise tolerance. These findings suggest that IMT may be a helpful adjunct to asthma management that has the potential to improve participation and adherence to exercise training in this group. However, the perception of breathlessness is also an important signal of bronchoconstriction, and thus, caution should be exercised if this symptom is abnormally low.

Dietary salt alters pulmonary function during exercise in exercise-induced asthmatics

Epidemiological and experimental studies have suggested that dietary salt may play a role in airway responsiveness. We have previously shown that a low salt diet improves and a high salt diet exacerbates post-exercise pulmonary function in individuals with exercise-induced asthma. The aim of this study was to determine the influence of both elevated and restricted salt diets on pulmonary function during exercise in individuals with exercise-induced asthma. Nine men and six women participated in this double-blind, crossover study. The participants entered the study on their normal salt diet and were placed on either a low or high salt diet for 2 weeks. Each diet was randomized, with a 1 week washout period between diets before crossing over to the alternative diet for 2 weeks. The participants underwent treadmill testing at 85% of their age-predicted heart rate on the normal salt diet and at the end of each treatment period. Pulmonary function was assessed during exercise by arterial saturation (ear oximetry) and indirect calorimetry. Twenty-four hour urine collections confirmed compliance with the diets. Arterial saturation was reduced on the high and improved on the low salt diet at higher exercise intensities. Tidal volume and frequency selection during exercise varied with the diets, with a higher tidal volume and lower frequency on the high salt diet, but a lower tidal volume and higher frequency on the low salt diet. This suggested greater airway resistance during the high salt diet. In conclusion, the low salt diet improved and the high salt diet exacerbated pulmonary function during exercise in individuals with exercise-induced asthma. The mechanism of action remains unclear.

Inspiratory flow resistive loading improves respiratory muscle function and endurance capacity in recreational runners

The purpose of this study was to assess the efficacy of inspiratory flow resistive loading (IFRL) on respiratory muscle function, exercise performance and cardiopulmonary and metabolic responses to exercise. Twenty‐four recreational road runners (12 male) were randomly assigned from each gender into an IFRL group (n=8) and sham‐IFRL group (n=8), which performed IFRL for 6 weeks, or a control group (n=8). Strength (+43.9%Δ), endurance (+26.6%Δ), maximum power output (+41.9%Δ) and work capacity (+38.5%Δ) of the inspiratory muscles were significantly increased (P<0.05) at rest following the study period in IFRL group only. In addition, ventilation (−25.7%Δ), oxygen consumption (−13.3%Δ), breathing frequency (−11.9%Δ), tidal volume (−16.0%Δ), heart rate (HR) (−13.1%Δ), blood lactate concentration (−38.9%Δ) and the perceptual response (−33.5%Δ) to constant workload exercise were significantly attenuated (P<0.05), concomitant with a significant improvement (P<0.05) in endurance exercise capacity (+16.4%Δ) during a treadmill run set at 80% in IFRL group only. These data suggest that IFRL can alter breathing mechanics, attenuate the oxygen cost, ventilation, HR, blood lactate and the perceptual response during constant workload exercise and improve endurance exercise performance in recreational runners.

Four-week pedometer-determined activity patterns in normal-weight, overweight and obese adults

OBJECTIVE To assess pedometer-determined ambulatory activity in normal-weight, overweight and obese UK adults. METHODS Eighty-six normal-weight (BMI <25 kg/m(2)) (age=34+/-12.1 years), 91 overweight (BMI 25-29.9 kg/m(2)) (age=40.6+/-13.6 years) and 75 obese (BMI >or= 30 kg/m(2)) (age=41.2+/-12.4 years) participants, from the East Midlands, provided 4 weeks of continuous pedometer-determined activity data, during the winter in 2006. Activity levels and patterns were assessed for all three groups. RESULTS The normal-weight group had a significantly higher mean step count (10247 steps/day) than the overweight (9095 steps/day) and obese (8102 steps/day) participants (p<0.05). No differences in step counts were observed between the overweight and obese groups. A consistent reduction in activity was observed on Sundays in all groups, with this reduction being two-fold greater in the overweight and obese groups (approximately 2000 steps/day) when compared with the normal-weight group (approximately 1000 steps/day). CONCLUSIONS With the increasing prevalence of obesity in the UK, changes in the activity levels of those at risk are needed. The issuing of pedometers to overweight and obese individuals, with the instruction to increase their ambulatory activity on all days of the week, with particular emphasis on Sunday activity, could be a good starting point in tackling the problem of obesity in the UK.

Omega-3 Polyunsaturated Fatty Acids in the Optimization of Physical Performance

Increased oxidative stress and inflammatory responses among individuals performing strenuous exercise, elite athletes, or military personnel have been consistently reported. In addition, it is known that exhaustive and/or unaccustomed exercise can lead to muscle fatigue, delayed onset muscle soreness, and a decrement in performance. Omega-3 polyunsaturated fatty acids (ω3PUFAs) have been shown to decrease the production of inflammatory eicosanoids, cytokines, and reactive oxygen species, to possess immunomodulatory effects, and to attenuate inflammatory diseases. Although, a number of studies have assessed the efficacy of ω3PUFA supplementation on red blood cell deformability, muscle damage, inflammation, and metabolism during exercise, only a few studies have evaluated the impact of ω3PUFA supplementation on exercise performance. This review demonstrates that, at present, we cannot conclude the hypothesis that ω3PUFA supplementation is effective and ergogenic, and that the data is inconclusive whether ω3PUFA supplementation effectively attenuates the inflammatory and immunomodulatory response to exercise. Future human studies should assess the effectiveness of ω3PUFA supplementation on delayed onset muscle soreness, and subsequent exercise performance, in multisport athletes and military personnel who typically engage in more than one bout of exercise per day using a more robust research design than those that have been used in previous studies.

N-3 fatty acids and asthma

Asthma is one of the most common and prevalent problems worldwide affecting over 300 million individuals. There is some evidence from observational and intervention studies to suggest a beneficial effect of n-3 PUFA in inflammatory diseases, specifically asthma. Marine-based n-3 PUFA have therefore been proposed as a possible complementary/alternative therapy for asthma. The proposed anti-inflammatory effects of n-3 fatty acids may be linked to a change in cell membrane composition. This altered membrane composition following n-3 fatty acid supplementation (primarily EPA and DHA) can modify lipid mediator generation via the production of eicosanoids with a reduced inflammatory potential/impact. A recently identified group of lipid mediators derived from EPA including E-series resolvins are proposed to be important in the resolution of inflammation. Reduced inflammation attenuates the severity of asthma including symptoms (dyspnoea) and exerts a bronchodilatory effect. There have been no major health side effects reported with the dietary supplementation of n-3 fatty acids or their mediators; consequently supplementing with n-3 fatty acids is an attractive non-pharmacological intervention which may benefit asthma.

Respiratory muscle specific warm-up and elite swimming performance

Background Inspiratory muscle training has been shown to improve performance in elite swimmers, when used as part of routine training, but its use as a respiratory warm-up has yet to be investigated. Aim To determine the influence of inspiratory muscle exercise (IME) as a respiratory muscle warm-up in a randomised controlled cross-over trial. Methods A total of 15 elite swimmers were assigned to four different warm-up protocols and the effects of IME on 100 m freestyle swimming times were assessed.Each swimmer completed four different IME warm-up protocols across four separate study visits: swimming-only warm-up; swimming warm-up plus IME warm-up (2 sets of 30 breaths with a 40% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); swimming warm-up plus sham IME warm-up (2 sets of 30 breaths with a 15% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); and IME-only warm-up. Swimmers performed a series of physiological tests and scales of perception (rate of perceived exertion and dyspnoea) at three time points (pre warm-up, post warm-up and post time trial). Results The combined standard swimming warm-up and IME warm-up were the fastest of the four protocols with a 100 m time of 57.05 s. This was significantly faster than the IME-only warm-up (mean difference=1.18 s, 95% CI 0.44 to 1.92, p<0.01) and the swim-only warm-up (mean difference=0.62 s, 95% CI 0.001 to 1.23, p=0.05). Conclusions Using IME combined with a standard swimming warm-up significantly improves 100 m freestyle swimming performance in elite swimmers.

Real-time monitoring of exhaled volatiles using atmospheric pressure chemical ionization on a compact mass spectrometer

AIM Breath analyses have potential to detect early signs of disease onset. Ambient ionization allows direct combination of breath gases with MS for fast, on-line analysis. Portable MS systems would facilitate field/clinic-based breath analyses. Results & methodology: Volunteers ingested peppermint oil capsules and exhaled volatile compounds were monitored over 10 h using a compact mass spectrometer. A rise and fall in exhaled menthone was observed, peaking at 60-120 min. Real-time analysis showed a gradual rise in exhaled menthone postingestion. Sensitivity was comparable to established methods, with detection in the parts per trillion range. CONCLUSION Breath volatiles were readily analyzed on a portable mass spectrometer through a simple inlet modification. Induced changes in exhaled profiles were detectable with high sensitivity and measurable in real-time.