Maximal Respiratory Pressures and Maximum Voluntary Ventilation in Young Arabs: Association with Anthropometrics and Physical Activity

Normative Values and Calculation Formulas of Respiratory Muscle Strength of Adults in Turkish Society: A Population-based Study

This study aimed to establish normative values for maximum inspiratory pressure and maximal expiratory pressure in the Turkish population while creating specific equations to calculate these values. The study involved 219 healthy adults, with a minimum of 50 individuals in specific age ranges: 20-29, 30-39, 40-49, and 50-60 years. Each age group comprised at least 25 males and 25 females. Participants were required to be free from health conditions influencing respiratory muscle strength and non-smokers. Measurements of maximum inspiratory pressure and maximal expiratory pressure were recorded for all participants. As a result of the regression analysis performed for the maximum inspiratory pressure values, the model P value was < .001, and the R2 value was found to be 0.261. The equation obtained as a result of the model was: 82.583 - 3.218 × gender - 0.093 × age+9.534 × height+0.343 × weight. As a result of the regression analysis performed for maximal expiratory pressure values, the model P value was <.001, and the R2 value was found to be 0.285. The equation obtained as a result of the model was: 157.165 - 35.522 × gender - 0.271 × age-42.036 × height+0.787 × weight. The newly developed equations offer valuable tools for evaluating respiratory muscle strength in the Turkish population. These results confirm the importance of using maximum inspiratory pressure and maximal expiratory pressure to monitor changes in each patient, while also emphasizing the necessity of reliable reference equations.

Maximal Respiratory Pressure Reference Equations in Healthy Adults and Cut-off Points for Defining Respiratory Muscle Weakness

INTRODUCTION

Maximal inspiratory and expiratory pressures (PImax/PEmax) reference equations obtained in healthy people are needed to correctly interpret respiratory muscle strength. Currently, no clear cut-off points defining respiratory muscle weakness are available. We aimed to establish sex-specific reference equations for PImax/PEmax in a large sample of healthy adults and to objectively determine cut-off points for respiratory muscle weakness.

METHODS

A multicentre cross-sectional study was conducted across 14 Spanish centres. Healthy non-smoking volunteers aged 18-80 years stratified by sex and age were recruited. PImax/PEmax were assessed using uniform methodology according to international standards. Multiple linear regressions were used to obtain reference equations. Cut-off points for respiratory muscle weakness were established by using T-scores.

RESULTS

The final sample consisted of 610 subjects (314 females; 48 [standard deviation, SD: 17] years). Reference equations for PImax/PEmax included body mass index and a squared term of the age as independent variables for both sexes (p<0.01). Cut-off points for respiratory muscle weakness based on T-scores ≥2.5 SD below the peak mean value achieved at a young age were: 62 and 83cmH2O for PImax and 81 and 109cmH2O for PEmax in females and males, respectively.

CONCLUSION

These reference values, based on the largest dataset collected in a European population to date using uniform methodology, help identify cut-off points for respiratory muscle weakness in females and males. These data will help to better identify the presence of respiratory muscle weakness and to determine indications for interventions to improve respiratory muscle function.

Causal associations between hand grip strength and pulmonary function: a two-sample Mendelian randomization study

BACKGROUND

Several observational studies have reported an association between hand grip strength (HGS) and pulmonary function (PF). However, causality is unclear. To investigate whether HGS and PF are causally associated, we performed Mendelian randomization (MR) analyses.

METHODS

We identified 110 independent single nucleotide polymorphisms (SNPs) for right-hand grip strength (RHGS) and 103 independent SNPs for left-hand grip strength (LHGS) at the genome-wide significant threshold (P < 5 × 10-8) from MRC-IEU Consortium and evaluated these related to PF. MR estimates were calculated using the inverse-variance weighted (IVW) method and multiple sensitivity analyses were further performed.

RESULTS

Genetical liability to HGS was positively causally associated with forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), but not with FEV1/FVC. In addition, there was positive causal association between RHGS and FVC (OR=1.519; 95% CI, 1.418-1.627; P=8.96E-33), and FEV1 (OR=1.486; 95% CI, 1.390-1.589; P=3.19E-31); and positive causal association between LHGS and FVC (OR=1.464; 95% CI, 1.385-1.548; P=2.83E-41) and FEV1 (OR=1.419; 95% CI, 1.340-1.502; P=3.19E-33). Nevertheless, no associations were observed between RHGS and FEV1/FVC (OR=0.998; 95% CI, 0.902-1.103; P=9.62E-01) and between LHGS and FEV1/FVC (OR=0.966; 95% CI, 0.861-1.083; P=5.52E-01). Similar results were shown in several sensitivity analyses.

CONCLUSION

Our study provides support at the genetic level that HGS is positively causally associated with FVC and FEV1, but not with FEV1/FVC. Interventions for HGS in PF impairment deserve further exploration as potential indicators of PF assessment.

The relationship of respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in post‐stroke hemiplegic patients

BACKGROUND

Cardiorespiratory system involvement and early fatigue observed in stroke patients complicate the rehabilitation process and affect their ability to perform daily activities and functional independence.

AIM

It was aimed to determine the relationship between respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in hemiplegic patients after stroke.

MATERIALS AND METHODS

Twenty-five volunteers who were diagnosed with post-stroke hemiplegia were included in the study. Sociodemographic and physical characteristics were recorded. Pulmonary function test (PFT), respiratory muscle strength, Trunk Impairment Scale (TIS), Timed-Up and Go Test (TUG), and Barthel Index (BI) were applied.

RESULTS

There was a moderate negative correlation between TUG scores and PFT results (r = 0.413-0.502; p = 0.011-0.04), except for PEF (%) and FEV1/FVC. Also, there were statistically significant correlation between TIS scores and FEV1(%) (r = 0.505; p = 0.012), FVC(%) (r = 0.449; p = 0.024). On the other hand, there was no statistically significant relationship between BI results and any parameter of the PFT (p > 0.05). There was no statistically significant correlation between respiratory muscle strength and TUG, TIS, BI (p > 0.05).

CONCLUSION

It has been shown that respiratory functions are associated with functional capacity and trunk control. However, it was found that there was no relationship between respiratory muscle strength and functional capacity, trunk control, and functional independence. It is thought that considering these parameters in the assessment of patients will contribute to the creation of individual and effective rehabilitation programs. The respiratory system should be systematically assessed in stroke rehabilitation and considered as part of a holistic approach.

CLINICAL TRIAL REGISTRATION

NCT05290649 (retrospectively registered) (clinicaltrials.gov).