The 2018 Physical Activity Guidelines for Americans: What's New? Implications for Clinicians and the Public

Differences among physical activity actigraphy algorithms in three chronic illness populations

OBJECTIVES

In three chronic illness populations and in a combined sample, we assessed differences in two algorithms to determine wear time (WT%) and four algorithms to determine: Kilocalories, light physical activity (PA), moderate-to-vigorous PA (MVPA), and metabolic equivalents (METs).

METHODS

Data were collected from 29 people living with HIV (PLHIV), 27 participants recovering from a cardiac event, and 15 participants with hypertension (HTN). Participants wore the ActiGraphTM wGT3X-BT for > 3 days on their hip. Analysis of variance (ANOVA) was used to assess differences among the algorithms.

RESULTS

No differences were found between the two algorithms to assess WT% or among the four algorithms to assess kilocalories in each of the chronic illness populations or in the combined sample. Significant differences were found among the four algorithms for light PA (p < .001) and METs (p < .001) in each chronic illness population and in the combined sample. MVPA was significantly different among the four algorithms in the PLHIV (p = .007) and in the combined sample (p < .001), but not in the cardiac (p = .064) or HTN samples (p = .200).

DISCUSSION

Our findings indicate that the choice of algorithm does make a difference in PA determination. Differences in algorithms should be considered when comparing PA across different chronic illness populations.

Oxidative status alteration during aerobic-dominant mixed and anaerobic-dominant mixed effort in judokas

This study aimed to depict the oxidative status variation in judokas during aerobic-dominant mixed effort (AeDME) and anaerobic-dominant mixed effort (AnDME). It is to be expected that the sporting commitment of Judo is a stimulus of oxidative stress leading to the recruitment of antioxidant responses. Blood samples were collected from 17 athletes at rest, immediately after a training session (AeDME) and after a 5-min bout (AnDME). AeDME and AnDME caused significant increases in malondialdehyde (MDA) (p < 0.01 and p < 0.001 respectively) and glutathione (GSH) (p = 0.018 and p < 0.001 respectively). Blood thiol concentrations decreased following AeDME and AnDME (p < 0.001) whilst catalase decreased significantly after AnDME (p = 0.026) only. Uric acid increased significantly after AnDME than after AeDME (p = 0.047) while, conversely, total bilirubin was higher after AnDME than after AeDME (p = 0.02). We may ultimately summarize that AeDME and AnDME caused oxidative stress, higher in AnDME, and some antioxidant response slightly higher in AnDME compared to AeDME. In sports, monitoring of oxidative stress status is recommended as part of the training regimen.

The Association Between Objectively-Measured Physical Activity and Cognitive Functioning in Middle-Aged and Older People Living with HIV

Middle-aged and older people living with HIV (PWH) are at higher risk for cognitive impairment and engage in lower levels of physical activity (PA) than seronegative counterparts. Research examining the association between objectively-measured PA and cognitive function in this population is scarce. This cross-sectional study examined the association between accelerometry-measured PA and cognitive functioning among 75 PWH (mean age 55.63). Light PA was the PA variable with the most consistent associations with cognition, with more minutes per week of light PA (performed in bouts of ≥ 10 min) being associated with better executive function, working memory/attention, and speed of processing performance, adjusted for age and current CD4 count. Findings suggest that although middle-aged and older PWH engage in more light than moderate-to-vigorous PA, light PA may be beneficial to cognition. Longitudinal studies are needed to understand PA dose-response associations with cognitive trajectories, cognitive domain specificity of PA effects, and underlying neural mechanisms of PA.

Cutting edge concepts: Does bilirubin enhance exercise performance?

Exercise performance is dependent on many factors, such as muscular strength and endurance, cardiovascular capacity, liver health, and metabolic flexibility. Recent studies show that plasma levels of bilirubin, which has classically been viewed as a liver dysfunction biomarker, are elevated by exercise training and that elite athletes may have significantly higher levels. Other studies have shown higher plasma bilirubin levels in athletes and active individuals compared to general, sedentary populations. The reason for these adaptions is unclear, but it could be related to bilirubin's antioxidant properties in response to a large number of reactive oxygen species (ROS) that originates from mitochondria during exercise. However, the mechanisms of these are unknown. Current research has re-defined bilirubin as a metabolic hormone that interacts with nuclear receptors to drive gene transcription, which reduces body weight. Bilirubin has been shown to reduce adiposity and improve the cardiovascular system, which might be related to the adaption of bilirubin increasing during exercise. No studies have directly tested if elevating bilirubin levels can influence athletic performance. However, based on the mechanisms proposed in the present review, this seems plausible and an area to consider for future studies. Here, we discuss the importance of bilirubin and exercise and how the combination might improve metabolic health outcomes and possibly athletic performance.

Changes in dual-task cognitive performance elicited by physical exertion vary with motor task

Background

Integrated movement and cognitive load paradigms are used to expose impairments associated with concussion and musculoskeletal injury. There is currently little information on the discriminatory nature of dual-task complexity and the relative influence of physical exertion on cognitive outcomes.

Purpose

Assess cognitive performance while under motor conditions of increasing complexity before and after a standardized exercise protocol.

Methods

34 participants were recruited (17 male and 17 female; 24 ± 1.4 yrs). A modified Eriksen flanker test was used to assess cognitive performance under four conditions (seated, single-leg stance, walking, and lateral stepping) before and after a 20-min moderate-to vigorous intensity treadmill protocol. The flanker test consisted of 20 sets of 5-arrow configurations, appearing in random order. To complete the response to cognitive stimulus, participants held a smartphone horizontally and were instructed to respond as quickly and as accurately as possible by tilting the device in the direction corresponding to the orientation of the middle arrow. The metrics used for analysis included average reaction time (ms), inverse efficiency index (average reaction time penalized for incorrect responses), and conflict effect (the average time cost of responding to an incongruent repetition vs. a congruent repetition). Mixed effects (condition by time) RMANOVAs were conducted to examine the effects of motor task complexity and physical exertion on cognitive performance.

Results

There was a condition by time interaction for inverse efficiency index (p < 0.001), in which participants displayed higher cognitive efficiency for the pre-activity lateral stepping condition compared to the other three conditions (Cohen's d = 1.3–1.6). For reaction time and conflict effect, there were main effects for condition (p = 0.004 and 0.006, respectively), in which performance during lateral stepping was improved in relation to the seated condition (reaction time Cohen's d = 0.68; conflict effect Cohen's d = 0.64).

Conclusion

Participants tended to display better dual-task cognitive performance under more stimulating or complex motor tasks before physical exertion, likely associated with the inverted-U arousal-performance relationship. When using dual-task assessments, clinicians should be mindful of the accompanying motor task and baseline exertion levels and their potential to disrupt or optimize cognitive performance.

The Effects of 5-HTP on Body Composition: An 8-Week Preliminary RCT

The purpose of this investigation was to determine the effects of supplementing with 100 mg daily of 5-Hydroxytryptophan (5-HTP) on indices of body composition in exercise-trained men and women. Sixty-one subjects volunteered for this investigation. Forty-eight subjects were randomized into a treatment (n = 31, 12 male/19 female; 100 mg 5-HTP daily; CLEANMOOD™) or a placebo (n = 17, six male/11 female; maltodextrin). Body composition was assessed pre- and post-treatment after eight weeks via a multi-frequency bioelectrical impedance device (InBody® 270). Subjects were instructed to not change their training or eating habits; moreover, they were instructed to track their diet ∼2-3 days per week using a mobile app (MyFitnessPal). There were no changes in food intake (i.e. total energy intake or grams of macronutrients) between or within groups. Lean body mass, total body water, and % body fat did not change significantly in either group. Fat mass decreased significantly post versus pre in the 5-HTP group (p = 0.02) but did not change in the placebo group (p = 0.58). Moreover, changes in fat mass were significantly different between the 5-HTP and placebo group (p = 0.048). Based on the limited data from this investigation, daily supplementation with 100 mg of 5-HTP may affect body composition.

Safety, efficacy and delivery of isometric resistance training as an adjunct therapy for blood pressure control: a modified Delphi study

Uncontrolled hypertension remains the major risk factor for cardiovascular disease. Isometric resistance training (IRT) has been shown to be a useful nonpharmacological therapy for reducing blood pressure (BP); however, some exercise physiologists and other health professionals are uncertain of the efficacy and safety of IRT. Experts' consensus was sought in light of the current variability of IRT use as an adjunct treatment for hypertension. An expert consensus-building analysis (Delphi study) was conducted on items relevant to the safety, efficacy and delivery of IRT. The study consisted of 3 phases: (1) identification of items and expert participants for inclusion; (2) a two-round modified Delphi exercise involving expert panelists to build consensus; and (3) a study team consensus meeting for a final item review. A list of 50 items was generated, and 42 international experts were invited to join the Delphi panel. Thirteen and 10 experts completed Delphi Rounds 1 and 2, respectively, reaching consensus on 26 items in Round 1 and 10 items in Round 2. The study team consensus meeting conducted a final item review and considered the remaining 14 items for the content list. A final list of 43 items regarding IRT reached expert consensus: 7/10 items on safety, 11/11 items on efficacy, 10/12 items on programming, 8/10 items on delivery, and 7/7 on the mechanism of action. This study highlights that while experts reached a consensus that IRT is efficacious as an antihypertensive therapy, some still have safety concerns, and there is also ongoing conjecture regarding optimal delivery.

"How Come You Sent Me the Canadian One?" Application and Uptake of the Canadian Physical Activity Guidelines for Adults With Multiple Sclerosis in the United States

The uptake and benefits of the Canadian Physical Activity Guidelines for Adults with Multiple Sclerosis (PAGs) have been validated, but there is limited understanding regarding the knowledge, needs, and preferences of people with multiple sclerosis (MS) for implementing the PAGs outside of clinical research. The authors conducted online, semistructured interviews with 40 persons with MS from across the United States seeking information on awareness of and potential approaches for increasing the uptake of the PAGs. They identified first impressions and potential approaches for increasing the uptake of the PAGs through inductive, semantic thematic analysis. Participants perceived the PAGs as a good introduction for structured exercise but desired more information on how to meet the PAGs. Participants further believed that modifying the PAGs for inclusivity and applying a multifaceted approach for dissemination and implementation may increase uptake of exercise behavior. Physical activity research in MS should include both analyzing the effects of exercise and the unique challenges faced by persons with MS in putting the PAGs into practice.

Untapping the Health Enhancing Potential of Vigorous Intermittent Lifestyle Physical Activity (VILPA): Rationale, Scoping Review, and a 4-Pillar Research Framework

Recently revised public health guidelines acknowledge the health benefits of regular intermittent bouts of vigorous intensity incidental physical activity done as part of daily living, such as carrying shopping bags, walking uphill, and stair climbing. Despite this recognition and the advantages such lifestyle physical activity has over continuous vigorous intensity structured exercise, a scoping review we conducted revealed that current research in this area is, at best, rudimentary. Key gaps include the absence of an empirically-derived dose specification (e.g., minimum duration of lifestyle physical activity required to achieve absolute or relative vigorous intensity), lack of acceptable measurement standards, limited understanding of acute and chronic (adaptive) effects of intermittent vigorous bouts on health, and paucity of essential information necessary to develop feasible and scalable interventions (e.g., acceptability of this kind of physical activity by the public). To encourage collaboration and research agenda alignment among groups interested in this field, we propose a research framework to further understanding of vigorous intermittent lifestyle physical activity (VILPA). This framework comprises four pillars aimed at the development of: (a) an empirical definition of VILPA, (b) methods to reliably and accurately measure VILPA, (c) approaches to examine the short and long-term dose-response effects of VILPA, and (d) scalable and acceptable behavioural VILPA-promoting interventions.

Validity of Tools to Measure Physical Activity in Older Adults Following Total Knee Arthroplasty

Few validated tools exist for measuring physical activity following total knee arthroplasty (TKA) despite the importance of returning to sufficient levels of physical activity post-TKA to achieve health benefits. This study examined the validity of two clinical measures-the Fitbit, a commercially available personal activity monitor, and the Community Healthy Activities Model Program for Seniors (CHAMPS), a self-report questionnaire-compared with a reference standard accelerometer, the SenseWearTM Armband (SWA). At 6-month post-TKA, 47 participants wore the Fitbit and SWA for 4 days and then completed the CHAMPS. Moderate-to-good correlation was observed between the Fitbit and SWA for steps (intraclass correlation coefficient [ICC] = .79), energy expenditure (ICC = .78), and energy expenditure <3 METS (ICC = .79). Poor-to-moderate correlation was observed between the CHAMPS and SWA (ICC = .43) with the questionnaire reporting lower daily energy expenditures than the SWA. Results showed that Fitbit may be a reasonable measurement tool to measure steps and energy expenditures in older adults following TKA.

Motivation and exercise in rural postmenopausal women: A literature review

PURPOSE

Most rural Americans are not meeting recommended guidelines for physical activity (PA); rural postmenopausal women (RPMW) have the highest inactivity rates. Self-Determination Theory, a motivational theory which examines the effects of qualitatively different types of motivation is used to conceptualize how RPMW make decisions regarding PA. The purpose of this review is to examine published literature related to motivation and exercise or PA in RPMW. The research questions include (a) what is known about the relationship of motivation to exercise in RPMW; and (b) how have motivation and exercise been measured in RPMW?

METHODS

An electronic database search resulted in a sample of 251 articles, with an additional 9 articles acquired by scanning reference lists. Search terms included motivation, exercise, rural women, urban women, and PA. Criteria for inclusion were postmenopausal women, primary research published before 2019, reported in English, and taking place in the United States.

FINDINGS

Thirteen articles involving RPMW were included. The sample contained four qualitative, eight quantitative, and one mixed-method studies. There is little research regarding motivation and PA in RPMW. Barriers and facilitators to PA have been measured. Motivation was mentioned in two studies but not measured. PA is most often measured with self-report questionnaires.

CONCLUSION

The decision to be active or sedentary is embedded in motivation. Additional research that objectively measures both motivation and PA in a consistent manner is required to provide a knowledge base regarding motivation and PA behavior in RPMW.

The Role of Physical Therapists in Fighting the Type 2 Diabetes Epidemic

BACKGROUND

In 2014, the total prevalence of diabetes was estimated to be 422 million people worldwide. Due to the aging population and continued increase in obesity rates, the prevalence is expected to rise to 592 million by 2035. Diabetes can lead to several complications, including cardiovascular disease, stroke, peripheral arterial disease, nephropathy, neuropathy, retinopathy, lower extremity amputation, and musculoskeletal impairments.

CLINICAL QUESTION

Up to 80% of patients referred for outpatient physical therapy have diabetes or are at risk for diabetes, providing an opportunity for physical therapists to intervene. Therefore, we asked, "What is the role of physical therapists in fighting the diabetes epidemic?"

KEY RESULTS

Physical therapists commonly prescribe physical activity for the treatment of diabetes and other chronic diseases, such as cardiovascular disease and osteoarthritis. Physical therapists may also screen for risk factors for diabetes and diabetes-related complications and modify traditional musculoskeletal exercise prescription accordingly. Physical therapists must advocate for regular physical activity as a key component of the treatment of chronic diseases in all patient interactions.

CLINICAL APPLICATION

This commentary (1) describes the diabetes epidemic and the health impact of diabetes and diabetes-related complications, (2) highlights the physical therapist's role as front-line provider, and (3) provides recommendations for physical therapists in screening for diabetes risk factors and diabetes-related complications and considerations for patient management. We focus on type 2 diabetes. J Orthop Sports Phys Ther 2020;50(1):5-16. Epub 28 Nov 2019. doi:10.2519/jospt.2020.9154.