Research Extracts: HIIT exercise | Hypertension treatment | Fatty fish and asthma
Welcome to the December edition of Thorne’s Research Extracts. This is Thorne’s monthly research update on diet, nutrient, botanical, and lifestyle approaches to good health. Knowing that busy practitioners can’t always focus on the latest research, our medical team of NDs, MDs, PhDs, RDs, and MS (Biol) has summarized the essence of the very most interesting studies.
In this issue: (1) sitting versus sitting interrupted by high intensity exercise, (2) pitfalls of pharmaceutical treatment for mild hypertension, (3) the Mediterranean Diet supplemented with fatty fish for childhood asthma, and (4) health risks of sitting versus smoking.
Effects of intermittent high-intensity exercise during periods of prolonged sitting
Prolonged sitting in the workplace has deleterious health consequences. Although high-intensity interval training (HIIT) can be a time-effective exercise strategy for certain health benefits, it may distract workers from tasks that require concentration or executive function.
Therefore, the current study aimed to examine the effects of just six minutes of HIIT on circulatory, metabolic, hormonal, thermoregulatory, cognitive, and perceptual responses while sitting.
Twelve students (age, 22 ± 2 years) performed a cross-over trial with two arms: sitting for 180 minutes, and sitting for 180 minutes with six minutes of HIIT training after 60 minutes of sitting.
Exercises included 25 rotating and repeated exercises of body weight squats, lunges, and jumping jacks, and skipping, running, and jogging in place.
Compared to sitting, after the HIIT exercise, blood lactate, heart rate, oxygen uptake, respiratory exchange ratio (RER), heart rate, odor, sweating, and perception of heat and vigor were all elevated, then RER and skin temperature decreased to lower than the sitting arm.
On average, the participants burned 109 more calories when exercising during the 180 minutes than when they were only sitting.
The study found no differences in levels of blood glucose, salivary cortisol, or Stroop test (a measure of cognitive function) between the two arms.
The researchers concluded that interrupting prolonged periods of sitting with six minutes of HIIT exercises influences circulatory and metabolic responses, without affecting hormonal, thermoregulatory or cognitive functions for better or worse.
When performed daily, six minutes of HIIT exercises during prolonged sitting supports substantial energy expenditure weekly. The researchers also suggested that if individuals engage in HIIT more than once daily, then they should sit for at least 60 minutes between exercising for circulation to return to baseline.
Contributed by Laura Kunces, PhD
- Sperlich B, De Clerck I, Zinner C, et al. Prolonged sitting interrupted by 6-min of high-intensity exercise: circulatory, metabolic, hormonal, thermal, cognitive, and perceptual responses. Front Physiol 2018 Oct 16;9:1279. doi: 10.3389/fphys.2018.01279.
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198043/ [Accessed Nov. 19, 2018]
Pharmaceutical treatment of mild hypertension not always best option
Most antihypertension treatment studies involve patients who have elevated blood pressure and are at high risk for cardiovascular disease (CVD). However, only minimal data exists for patients who have mild hypertension and low CVD risk.
British researchers collected data during 18 years from 38,286 patients who were mildly hypertensive (140/90 - 159/99 mm Hg) and had low CVD risk.
In this longitudinal cohort study, half of the patients received pharmacological intervention per the American College of Cardiology/American Heart Association (ACC/AHA) guidelines, whereas the other half were not prescribed any drugs by their physicians.
The results of the study found no reduction in risk for all-cause mortality or for cardiovascular incidents (hazard ratio (HR), 1.02 and 1.09, respectively) with antihypertensive treatment.
However, an increased incidence of adverse events was observed with treatment, including hypotension (HR = 1.69), syncope (HR = 1.28), electrolyte abnormalities (HR = 1.72), and acute kidney injury (HR = 1.37).
Based on these results, the authors suggest health-care practitioners should consider CVD risk level before prescribing pharmacological treatments for mild hypertension (ACC/AHA stage 1 or 2).
Contributed by Sheena Smith, MS (Biol)
- Sheppard J, Stevens S, Stevens R, et al. Benefits and harms of antihypertensive treatment in low-risk patients with mild hypertension. JAMA Intern Med 2018 Oct 29. doi:10.1001/jamainternmed.2018.4684. [Epub ahead of print]
Mediterranean Diet with added fatty fish benefits childhood asthma
The Mediterranean Diet, as well as diets high in fish that contain omega-3 fatty acids, have been shown in numerous studies to confer anti-inflammatory effects. The effect of diet on pulmonary function was tested in 64 Greek children (ages 5-12 years) who had mild asthma.
The children were randomized to either their regular Mediterranean-style diet (control) or that same diet plus two meals per week of 150 grams of cooked fatty fish (intervention) for six months.
In the intervention group, daily fish intake increased from an average of 17 grams to 46 grams.
Bronchial inflammation was measured by fractional exhaled nitric oxide analysis, measured in parts per billion (ppb). Respiratory function was assessed by spirometry; quality of life scores were also assessed.
After six months, and adjusting for body mass index, age, gender, and level of physical activity, inflammation scores significantly improved in the group who had the additional dietary fish intake.
Their airway inflammation scores decreased an average of 14 units (above 10 units is considered to be significant by international standards). No significant changes were noted in spirometry or quality of life scores.
The authors concluded that, “A Mediterranean diet supplemented with two fatty fish meals per week might be a potential strategy for reducing airway inflammation in childhood asthma.”
Contributed by Kathi Head, ND
- Papamichael M, Katsardis C, Lambert K, et al. Efficacy of a Mediterranean diet supplemented with fatty fish in ameliorating inflammation in paediatric asthma: a randomised controlled trial. J Hum Nutr Diet 2018 Oct 30. doi: 10.1111/jhn.12609. [Epub ahead of print]
Review of evidence: sitting is not the new smoking!
The recent proposition that prolonged sitting is just as dangerous as smoking has been spread by major media outlets and has even found its way into academic and clinical arenas – media mentions of this pseudofact increased 12-fold from 2012 to 2016.
This study’s review of available evidence concluded that although sitting longer than eight hours per day does have adverse effects on various personal health factors, these adverse effects pale in comparison to the adverse effects that smoking has on those same personal health factors.
The global health impact of physical inactivity – defined as a failure to engage in 150 minutes of moderate activity per week – was estimated at $53.8 billion in 2013. Prolonged sitting has now been associated with a two-fold increase in type 2 diabetes risk, as well as a 10-20 percent increased risk of premature death.
In contrast, smokers have approximately a 180-percent increase of premature death compared to non-smokers, resulting in a global health impact of $467 billion in 2013.
Furthermore, smokers have more than double the risk of developing several types of cancers and cardiovascular disease, as well as more than a 10-fold increase in lung cancer risk compared to non-smokers.
Contributed by Joel Totoro, RD
- Vallance J, Gardiner P, Lynch B, et al. Evaluating the evidence on sitting, smoking, and health: is sitting really the new smoking? Am J Public Health 2018;108(11):1478-1482.
- https://ajph.aphapublications.org/doi/full/10.2105/AJPH.2018.304649 [Accessed Nov. 19, 2018]