Biochemical, Physiological and Psychological Changes During Endurance Exercise in People With Type 1 Diabetes.
Increasing numbers of people with diabetes are adopting exercise programs. Fear of hypoglycemia, hypoglycemia itself, and injuries are major issues for many people with diabetes undertaking physical activity. The purpose of this study was to investigate the effects of type 1 diabetes mellitus on the risk of hypoglycemia, glycemic variability, exercise performance, changes in body composition, changes in insulin dosage, and psychosocial well-being during a multiday endurance exercise event.



Eleven participants (7 with type 1 diabetes, 4 with normal glucose tolerance) undertook a 15-day, 2300 km cycling tour from Barcelona to Vienna. Data were prospectively collected using bike computers, continuous glucose monitors, body composition analyzers, and mood questionnaires.



Mean blood glucose in riders with and without diabetes significantly reduced as the event progressed. Glycemic variability and time spent in hypoglycemia did not change throughout the ride for either set of riders. Riders with diabetes in the lowest quartile of sensor glucose values had significantly reduced power output. Percentage body fat also significantly fell. Hypo- and hyperglycemia provoked feelings of anxiety and worry.



This is the first study to describe a real-time endurance event in type 1 diabetes, and provides important new data that cannot be studied in laboratory conditions. Hypoglycemia continues to occurs in spite of peer support and large reductions in insulin dose. Glycemic variability is shown as a potential barrier to participation in physical activity through effects on mood and psychological well-being.
1 Department of Diabetes & Endocrinology, Charing Cross Hospital, London, UK.|2 Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK.
Neil E
NE
Hill
1 Department of Diabetes & Endocrinology, Charing Cross Hospital, London, UK.
Christopher
C
Campbell
3 Team Blood Glucose, Nottingham, UK.
Paul
P
Buchanan
3 Team Blood Glucose, Nottingham, UK.
Midge
M
Knight
4 Diabetes Endocrinology and Metabolic Medicine, Faculty of Medicine, Imperial College London, St. Mary's Campus, London, UK.
Ian F
IF
Godsland
1 Department of Diabetes & Endocrinology, Charing Cross Hospital, London, UK.
Nick S
NS
Oliver
D000328:Adult; D000368:Aged; D001786:Blood Glucose; D015190:Blood Glucose Self-Monitoring; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000523:psychology; D007003:Hypoglycemia / Q000523:psychology; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose
continuous glucose monitoring; endurance exercise; hypoglycemia; type 1 diabetes
Diabet Med. 2001 Nov;18(11):889-94
11703433
Diabetes Res Clin Pract. 2006 Jun;72(3):271-6
16406128
Diabetes. 2000 Jan;49(1):73-81
10615952
Diabetes Care. 1984 Nov-Dec;7(6):520-7
6391876
Diabetes Technol Ther. 2003;5(5):817-28
14633347
Metabolism. 2000 Mar;49(3):386-94
10726919
J Clin Invest. 2001 Dec;108(12):1875-81
11748271
Curr Sports Med Rep. 2012 Nov-Dec;11(6):309-15
23147019
Diabetes Obes Metab. 2015 Apr;17(4):343-9
25132320
Diabetes Care. 2008 Nov;31(11):2108-9
18689694
J Appl Physiol (1985). 2006 Sep;101(3):934-7
16763099
Diabetologia. 2012 Mar;55(3):542-51
22189486
Arterioscler Thromb Vasc Biol. 2000 Jun;20(6):1595-9
10845877
Diabetes Technol Ther. 2011 Sep;13(9):921-8
21714681
Am J Physiol. 1999 Oct;277(4 Pt 1):E733-41
10516134
Arch Intern Med. 2000 Nov 27;160(21):3278-85
11088090
Nature. 2003 Jun 12;423(6941):762-9
12802337
Int J Pediatr. 2010;2010:null
20811595
Diabetes Technol Ther. 2013 Apr;15(4):295-301
23427866
Diabetes. 1996 Feb;45(2):148-56
8549858
J Clin Invest. 1976 Mar;57(3):791-5
1249209
Diabetologia. 2003 Apr;46(4):459-69
12687327
Obes Rev. 2005 Feb;6(1):13-21
15655035
Curr Opin Endocrinol Diabetes Obes. 2009 Apr;16(2):150-5
19300093
Diabetes Care. 1987 Sep-Oct;10(5):584-8
3677976
Med Sci Sports Exerc. 2012 Feb;44(2):225-31
21716152