Changes in injection-site blood flow and plasma free insulin concentrations in response to stress in type 1 diabetic patients

Acute psychological stress affects glucose concentrations in patients with type 1 diabetes following food intake but not in the fasting state

OBJECTIVE

To compare the effect of acute psychosocial stress on glucose concentrations in the fasting state and following food intake in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

In study 1, 20 patients were exposed to moderate psychosocial stress by means of the Trier Social Stress Test (TSST) in the fasting state. In study 2, the TSST was applied to 20 additional patients 75 min after intake of a standard meal. Glucose concentrations (by continuous glucose monitoring system), blood pressure, and heart rate were monitored on the control day and on the stress testing day.

RESULTS

In both studies, blood pressure increased in response to TSST from 122/77 +/- 14/9 mmHg at baseline to a maximum of 152/93 +/- 21/13 mmHg (P < 0.001), and heart rate increased from 80 +/- 11 to 99 +/- 19 bpm (P < 0.001). In the fasting state (study 1), glucose concentrations remained unchanged during the control day as well as during the stress testing day. In study 2, glucose concentrations were similar on both days before and up to 75 min after the intake of the standard meal. However, a significant delay (of 45 min) in the decrease of glucose concentrations was induced by psychological stress. A two-factor repeated-measures ANOVA revealed a significant difference of glucose concentrations over time (F = 646.65/P < 0.001).

CONCLUSIONS

In the postprandial period, acute psychological stress induced a significantly delayed decrease of glucose concentrations, whereas in the fasting state, no effect on poststress glucose concentrations was observed.

Daily stress and glycaemic control in Type 1 diabetes: individual differences in magnitude, direction, and timing of stress-reactivity

The aim of this study was to investigate the relationships between daily stress and glycaemic control in 54 people with Type 1 diabetes over 21 days. Measures included daily reports of stress (hassles), four-times-daily blood glucose measurements, and HbA1c levels. Time-series analyses revealed considerable variation between individuals in the nature and extent of blood glucose response to stress (stress-reactivity). In approximately one-third of the sample, stress was significantly associated with either same- or next-day blood glucose levels (r-range: -0.79 to 0.58). The majority of stress-reactive individuals (20.4% of the sample) demonstrated a positive association between hassles and same-day blood glucose levels. A much less common effect was found in two individuals (3.7%), where hassles were related to decreased same-day blood glucose. 'Stress-reactive' individuals tended to have high HbA1c values at baseline (t(52) = 2.2; P < 0.05), and significant relationships between emotion-focused coping and blood glucose levels (r = 0.93; P < 0.01). In conclusion, although a significant majority of this sample was resistant to the effects of stress, marked individual differences were found in the nature and extent of stress-reactivity. Our study goes beyond other published results as it is longitudinal, uses time-series analyses and includes a relatively larger sample. Clinicians need to be aware of these individual differences in order to advise patients about anticipating and preventing stress-related disruptions of glycaemic control.

Acute mental stress impairs insulin sensitivity in IDDM patients

The effect of acute mental stress on insulin sensitivity was evaluated in ten IDDM patients, studied on two occasions (test day and control day) in random order and separated by a period of 1-3 weeks. Mental stress was evoked by a modified filmed version of Stroop's CWT for 20 min. On the control day, the patients were resting quietly during the corresponding period. Insulin sensitivity was estimated by an insulin (0.4 mU.kg-1 x min-1)-glucose (4.5 mg.kg-1 x min-1)-infusion test (IGIT) for 6.5 h. Mental stress evoked significant responses for adrenaline, cortisol and GH, their respective peak values being 0.27 +/- 0.05 nmol/l, 426 +/- 27 nmol/l and 7.6 +/- 1.8 micrograms/l, as well as increases in systolic and diastolic blood pressure and pulse rate The steady-state blood glucose levels, i.e. the mean blood glucose levels 3-6.5 h after the start of the IGIT, were significantly higher after stress, compared with those on the control day, 10.6 +/- 1.5 vs 8.7 +/- 1.4 mmol/l, p = 0.01, demonstrating impairment of the insulin sensitivity by mental stress. It is concluded that acute mental stress induces a state of insulin resistance in IDDM patients, which can be demonstrated by an IGIT to appear 1 h after maximal stress and to last more than 5 h.