Edward W.D. Colt

Pain sensitivity, mood and plasma endocrine levels in man following long-distance running: effects of naloxone

&NA; The effects of intense exercise on pain perception, mood, and plasma endocrine levels in man were studied under naloxone and saline conditions. Twelve long‐distance runners (mean weekly mileage = 41.5) were evaluated on thermal, ischemie, and cold presser pain tests and on mood visual analogue scales (VAS). Blood was drawn for determination of plasma levels of &bgr;‐endorphin‐like immunoreactivity (BEir), growth hormone (GH), adrenocorticotrophic hormone (ACTH), and prolactin (PRL). These procedures were undertaken before and after a 6.3 mile run at 85% of maximal aerobic capacity. Subjects participated on two occasions in a double‐blind procedure counterbalanced for drug order: on one day they received 2 i.v. injections of naloxone (0.8 mg in 2 ml vehicle each) at 20 min intervals following the run; on the other day, 2 equal volume injections of normal saline (2 ml). Sensory decision theory analysis of the responses to thermal stimulation showed that discriminability, P(A), was significantly reduced post‐run under the saline condition, a hypoalgesic effect; response bias, B, was unaffected. Ischemie pain reports were significantly reduced post‐run on the saline day, also a hypoalgesic effect. Naloxone reversed the post‐run ischemie but not thermal hypoalgesic effects. Joy, euphoria, cooperation, and conscientiousness VAS ratings were elevated post‐run; naloxone attenuated the elevation in joy and euphoria ratings only. Plasma levels of BEir, ACTH, GH, and PRL were significantly increased post‐run. The results show that long‐distance running produces hypoalgesia and mood elevation in man. The effects of naloxone implicate endogenous opioid neural systems as mechanisms of some but not all of the run‐induced alterations in mood and pain perception.

The effect of running on plasma β-endorphin

Abstract Plasma β-endorphin immunoactivity was measured by RIA in 26 trained long distance runners on 35 occasions before and after running. Mean total β-endorphin immunoactivity increased from 11.8 ± 1.8 (SEM) to 17.6 ± 3.1 pg/m1 in 20 runners after an easy run ( p = .067), and from 8.2 ± 1.03 to 28.0 ± 6.3 pg/ m 1 in 15 runners after a strenuous run (p = .008). Total β-endorphin immunoactivity in the plasma extracts of 7 runners before and after the strenuous run was further characterized by Sephadex G-50 chromatography in order to separate β-endorphin from corssreacting β-lipotropin (β-LPH). A rise in β-endorphin and β-LPH concentrations after running was noted in 5 out of 7 runners.

Quantitative Heel Ultrasonography, 25-Hydroxyvitamin D, and Urine Amino-terminal Cross-linking Telopeptide of Type I Collagen in Patients With a Recent Hip Fracture

Objective. This study examined quantitative heel ultrasonography (QUS), 25‐hydroxyvitamin D (25‐OHD) levels, and urine amino‐terminal cross‐linking telopeptide of type I collagen (NTX‐I) levels in patients with a recent osteoporotic hip fracture to see whether they were clinically useful. Methods. Stiffness index (SI) T scores from QUS, 25‐OHD levels, and urine NTX‐I levels were obtained in 53 female and 32 male patients with hip fractures. Sixty‐five female patients and 5 male patients attending our geriatric clinic were used for comparison. Results. The SI T scores of the hip fracture patients were less than those of the geriatric clinic patients. The difference was significant in female patients (P = .0001) but not in male patients (P = .1). Serum levels of 25‐OHD were less than 28 ng/mL in 50 of 59 patients and less than 5 ng/mL in 2 patients. Levels of urine NTX‐I were variable and were not correlated with other parameters. Conclusions. Patients who have had a hip fracture have a low SI determined by QUS; this is easy to perform, and it provides a baseline T score from which to assess treatment effects. Most of these patients are vitamin D deficient, and measurement of the 25‐OHD level would enable physicians to prescribe an appropriate dose of vitamin D. Urine NTX‐I measured shortly after a hip fracture is not clinically helpful.