No effect of ascorbate on cutaneous vasodilation and sweating in older men and those with type 2 diabetes exercising in the heat

Naoto Fujii, Robert D. Meade, Pegah Akbari, Jeffrey C. Louie, Lacy M. Alexander, Pierre Boulay, Ronald J. Sigal, Glen P. Kenny

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Aging and chronic disease such as type 2 diabetes (T2D) are associated with impairments in the body's ability to dissipate heat. To reduce the risk of heat-related injuries in these heat vulnerable individuals, it is necessary to identify interventions that can attenuate this impairment. We evaluated the hypothesis that intradermal administration of ascorbate improves cutaneous vasodilation and sweating in older adults via nitric oxide synthase (NOS)-dependent mechanisms during exercise in the heat and whether these improvements, if any, are greater in individuals with T2D. Older males with (n = 12, 61 ± 9 years) and without (n = 12, 64 ± 7 years) T2D performed two 30-min bouts of cycling at a fixed rate of metabolic heat production of 500 W (~70% peak oxygen uptake) in the heat (35°C); each followed by a 20- and 40-min recovery, respectively. Cutaneous vascular conductance (CVC) and sweat rate were measured at four intradermal microdialysis sites treated with either (1) lactated Ringer (Control), (2) 10 mmol/L ascorbate (an antioxidant), (3) 10 mmol/L L-NAME (non-selective NOS inhibitor), or (4) a combination of ascorbate + L-NAME. In both groups, ascorbate did not modulate CVC or sweating during exercise relative to Control (all P > 0.05). In comparison to Control, L-NAME alone or combined with ascorbate attenuated CVC during exercise (all P ≤ 0.05) but had no influence on sweating (all P > 0.05). We show that in both healthy and T2D older adults, intradermal administration of ascorbate does not improve cutaneous vasodilation and sweating during exercise in the heat. However, NOS plays an important role in mediating cutaneous vasodilation.

Original languageEnglish (US)
Article numbere13238
JournalPhysiological reports
Volume5
Issue number7
DOIs
StatePublished - Apr 2017

Fingerprint

Sweating
Vasodilation
Type 2 Diabetes Mellitus
Hot Temperature
Skin
Nitric Oxide Synthase
Blood Vessels
NG-Nitroarginine Methyl Ester
Exercise
Sweat
Thermogenesis
Microdialysis
Chronic Disease
Antioxidants
Oxygen
Wounds and Injuries

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

Fujii, Naoto ; Meade, Robert D. ; Akbari, Pegah ; Louie, Jeffrey C. ; Alexander, Lacy M. ; Boulay, Pierre ; Sigal, Ronald J. ; Kenny, Glen P. / No effect of ascorbate on cutaneous vasodilation and sweating in older men and those with type 2 diabetes exercising in the heat. In: Physiological reports. 2017 ; Vol. 5, No. 7.
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abstract = "Aging and chronic disease such as type 2 diabetes (T2D) are associated with impairments in the body's ability to dissipate heat. To reduce the risk of heat-related injuries in these heat vulnerable individuals, it is necessary to identify interventions that can attenuate this impairment. We evaluated the hypothesis that intradermal administration of ascorbate improves cutaneous vasodilation and sweating in older adults via nitric oxide synthase (NOS)-dependent mechanisms during exercise in the heat and whether these improvements, if any, are greater in individuals with T2D. Older males with (n = 12, 61 ± 9 years) and without (n = 12, 64 ± 7 years) T2D performed two 30-min bouts of cycling at a fixed rate of metabolic heat production of 500 W (~70{\%} peak oxygen uptake) in the heat (35°C); each followed by a 20- and 40-min recovery, respectively. Cutaneous vascular conductance (CVC) and sweat rate were measured at four intradermal microdialysis sites treated with either (1) lactated Ringer (Control), (2) 10 mmol/L ascorbate (an antioxidant), (3) 10 mmol/L L-NAME (non-selective NOS inhibitor), or (4) a combination of ascorbate + L-NAME. In both groups, ascorbate did not modulate CVC or sweating during exercise relative to Control (all P > 0.05). In comparison to Control, L-NAME alone or combined with ascorbate attenuated CVC during exercise (all P ≤ 0.05) but had no influence on sweating (all P > 0.05). We show that in both healthy and T2D older adults, intradermal administration of ascorbate does not improve cutaneous vasodilation and sweating during exercise in the heat. However, NOS plays an important role in mediating cutaneous vasodilation.",
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No effect of ascorbate on cutaneous vasodilation and sweating in older men and those with type 2 diabetes exercising in the heat. / Fujii, Naoto; Meade, Robert D.; Akbari, Pegah; Louie, Jeffrey C.; Alexander, Lacy M.; Boulay, Pierre; Sigal, Ronald J.; Kenny, Glen P.

In: Physiological reports, Vol. 5, No. 7, e13238, 04.2017.

Research output: Contribution to journalArticle

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T1 - No effect of ascorbate on cutaneous vasodilation and sweating in older men and those with type 2 diabetes exercising in the heat

AU - Fujii, Naoto

AU - Meade, Robert D.

AU - Akbari, Pegah

AU - Louie, Jeffrey C.

AU - Alexander, Lacy M.

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AB - Aging and chronic disease such as type 2 diabetes (T2D) are associated with impairments in the body's ability to dissipate heat. To reduce the risk of heat-related injuries in these heat vulnerable individuals, it is necessary to identify interventions that can attenuate this impairment. We evaluated the hypothesis that intradermal administration of ascorbate improves cutaneous vasodilation and sweating in older adults via nitric oxide synthase (NOS)-dependent mechanisms during exercise in the heat and whether these improvements, if any, are greater in individuals with T2D. Older males with (n = 12, 61 ± 9 years) and without (n = 12, 64 ± 7 years) T2D performed two 30-min bouts of cycling at a fixed rate of metabolic heat production of 500 W (~70% peak oxygen uptake) in the heat (35°C); each followed by a 20- and 40-min recovery, respectively. Cutaneous vascular conductance (CVC) and sweat rate were measured at four intradermal microdialysis sites treated with either (1) lactated Ringer (Control), (2) 10 mmol/L ascorbate (an antioxidant), (3) 10 mmol/L L-NAME (non-selective NOS inhibitor), or (4) a combination of ascorbate + L-NAME. In both groups, ascorbate did not modulate CVC or sweating during exercise relative to Control (all P > 0.05). In comparison to Control, L-NAME alone or combined with ascorbate attenuated CVC during exercise (all P ≤ 0.05) but had no influence on sweating (all P > 0.05). We show that in both healthy and T2D older adults, intradermal administration of ascorbate does not improve cutaneous vasodilation and sweating during exercise in the heat. However, NOS plays an important role in mediating cutaneous vasodilation.

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