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Canadian Respiratory Journal
Volume 21 (2014), Issue 1, Pages 43-50

Reference Values for Maximal Inspiratory Pressure: A Systematic Review

Isabela MB Sclauser Pessoa,1 Verônica Franco Parreira,2 Guilherme AF Fregonezi,3 A William Sheel,4 Frank Chung,5 and W Darlene Reid6,7,8

1Rehabilitation Sciences Graduation Program, School of Physical Education, Physiotherapy and Occupational Therapy, Brazil
2Department of Physical Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
3Department of Physical Therapy, Universidade Federal do Rio Grande do Norte, Natal, Brazil
4School of Kinesiology, University of British Columbia, Vancouver, Canada
5Department of Physical Therapy, Burnaby Hospital, Burnaby, Canada
6Department of Physical Therapy, University of British Columbia, Canada
7Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
8Institute for Heart and Lung Health, University of British Columbia, Vancouver, British Columbia, Canada

Copyright © 2014 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


BACKGROUND: Maximal inspiratory pressure (MIP) is the most commonly used measure to evaluate inspiratory muscle strength. Normative values for MIP vary significantly among studies, which may reflect differences in participant demographics and technique of MIP measurement.

OBJECTIVE: To perform a systematic review with meta-analyses to synthesize MIP values that represent healthy adults.

METHODS: A systematic literature search was conducted using Medline, EMBASE, Cochrane, Cumulative Index to Nursing and Allied Health (CINAHL) and Sport Discus databases. Two reviewers identified and selected articles, and abstracted data. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. A random-effects model was used to calculate overall means and 95% CIs.

RESULTS: Of 22 included articles, MIP data were synthesized according to age group and sex from six reports (n=840) in the meta-analyses. The mean QUADAS score was 3.5 of 7. The age range was between 18 and 83 years (426 men, 414 women). MIP began to decrease with age in the 40 to 60 years age range and continued to fall progressively with age. For the same age group, men tended to have higher MIPs than women. Sensitivity analysis of withdrawing studies from the meta-analysis identified one study that contributed more to heterogeneity in some age groups.

DISCUSSION: MIP was higher in men and decreased with age, which was initially apparent in middle age. Several characteristics of participants and MIP technique influence values in healthy individuals.

CONCLUSIONS: The present meta-analysis provides normative MIP values that are reflective of a large sample (n=840) and likely represents the broadest representation of participant characteristics compared with previous reports of normative data.