The use of an isometric handgrip test to show autonomic damage in people with diabetes.
BACKGROUND
Vascular endothelial and autonomic damage are hallmarks of type 1 and type 2 diabetes. However, while much has been published on impairment of the autonomic nervous system, much less has been published on the interrelationship between autonomic damage and exercise.


METHODS
The present investigation examined the change in heart rate, blood pressure, skin and limb blood flow, and sweat during non-fatiguing (10% and 25% maximum strength [maximal voluntary contraction (MVC)]) and a fatiguing isometric contraction (40% MVC) in people with type 2 diabetes compared to younger and older controls to see if a simple handgrip test could show the extent of autonomic damage in people with diabetes. Fifteen younger subjects (30.6 +/- 8.6 years), 15 older subjects (65.8 +/- 8.8 years), and 15 subjects with diabetes (63.4 +/- 14.4 years) whose average percentage body fat was 40.1 +/- 12.9%, 36.1 +/- 9.3%, and 39.6 +/- 15.5%, respectively, participated in these studies. Whole forearm blood flow, skin blood flow, and sweat on the forearm, chest, and forehead were measured at rest and during and after a contraction at 10% MVC, 25% MVC, and 40% MVC.


RESULTS
Blood flows and sweat rates were greatest in younger subjects, significantly less in older subjects, and even significantly less in subjects with diabetes (P < 0.05). The heart rate response was unaltered during contractions at 10% and 25% MVC and less in diabetes than in the other two groups with 40% MVC. Strength was about half in the diabetes group than with the other two groups, but endurance was similar.


CONCLUSIONS
Diabetes is associated with a reduction in handgrip strength and significantly impaired autonomic function during and after isometric exercise.
Petrofsky
Jerrold
J
Department of Physical Therapy, Loma Linda University, Loma Linda, California 92350, USA. jpetrofsky@llu.edu
Prowse
Michelle
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Remigio
Wilton
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Salcedo
Samuel
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Melissa
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Madani
Piyush
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Chamala
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Puckett
Eryn
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Wong
May
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Fajita
Matthew
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Ramneek
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Moore
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Pereira
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Katikaneni
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Regula
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Elavarthy
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Kumar
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Gadagoju
Ashita
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D000328:Adult; D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis* / Q000503:physiopathology; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000503:physiopathology; D015444:Exercise; D005542:Forearm / Q000098:blood supply; D018737:Hand Strength / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D007537:Isometric Contraction; D008875:Middle Aged; D009119:Muscle Contraction; D012016:Reference Values; D012867:Skin / Q000098:blood supply; D055815:Young Adult