Quotes by Ray Peat, PhD:
“One of the oldest tests for hypothyroidism was the Achilles tendon reflex test in which the rate of relaxation of the calf muscle corresponds to thyroid function–the relaxation is slow in hypothyroid people. Water, sodium, and calcium are more slowly expelled by the hypothyroid muscle. Exactly the same slow relaxation occurs in the hypothyroid heart muscle, contributing to heart failure, because the semi-contracted heart can’t receive as much blood as the normally relaxed heart. The hypothyroid blood vessels are unable to relax properly, contributing to hypertension. Hypothyroid nerves don’t easily return to their energized relaxed state, leading to insomnia, parasthesias, movement disorders, and nerves that are swollen and very susceptible to pressure damage.”
“There are several convenient indicators of the metabolic rate–the daily temperature cycle and pulse rate (the temperature should rise after breakfast), the amount of water lost by evaporation, and the speed of relaxation of muscles (Achilles reflex relaxation).”
“Measuring the speed and relaxation of the Achilles tendon reflex twitch is a traditional method for judging thyroid function, because in hypothyroidism the relaxation is visibly delayed.”
The achilles tendon reflex can be used to assess thyroid function (Woltman’s Sign). The foot should plantar flex quickly and then return immediately to its starting position or beyond with no hesitation if the metabolism is healthy. No response or a very slow return back to original position are indicative of low metabolism.
Minerva Med. 1976 Oct 27;67(51):3325-34.
[Achilles reflexogram and hemodynamic parameters in the evaluation of thyroid function].
[Article in Italian]
Franco G, Malamani T.
Among the numerous techniques designed to explore thyroid function, two which examine important peripheral aspects are considered: Achilles osteotendinous reflectivity (determination of contraction time and relaxation time of the gastrocnemius muscle) and the response of the cardiovascular system to thyroid hormones (determination of the time of onset of Korotkoff’s sound and that of the brachial sphygmic wave). Comparison of the results obtained with these two techniques in a group of 60 euthyroid subjects, 17 hypothyroid and 25 hyperthyroid cases, shows that the techniques are comparable as regards precision, reproducibility, and sensitivity and are of indubitable importance for the assessment of thyroid function through the study of two of its peripheral aspects.
Probl Endokrinol (Mosk). 1982 Jan-Feb;28(1):34-8.
[Reflexometry as a supplementary study method in thyroid hypofunction].
[Article in Russian]
Gaĭdina GA, Matveeva LS, Lazareva SP.
A correlation was established between the time of the Achilles reflex and the biochemical characteristics of thyroid function (total thyroxin and triiodothyronine levels, thyroxin-binding capacity of the blood serum proteins, the basal TTH level) in patients with grave and moderately expressed hypothyroidism. This correlation was retained during the substitution therapy: however, the reflex time recovery was retarded as compared to the degree of manifestation of the clinical symptoms and normalization of the biochemical parameters. The time of the Achilles jerk may serve as an additional criterion in evaluating the hypothyrosis severity and the effect of the treatment.
J Assoc Physicians India. 1990 Mar;38(3):201-3.
Ankle reflex photomotogram in thyroid dysfunctions.
Khurana AK, Sinha RS, Ghorai BK, Bihari N.
The tap to half relaxation time of tendon achilles reflex was measured in thirty control subjects, forty-five thyrotoxic and sixty hypothyroid patients. The half relaxation time in the control males and females was 279.33 +/- 76.39 msec and 320.00 +/- 52.37 msec. respectively. In thyrotoxic males and females the half relaxation time was 256.67 +/- 31.62 msec (P less than 0.01) and 252.50 +/- 47.68 msec (P less than 0.01) respectively. Amongst the hypothyroid male and female patients the half relaxation time was 405.0 +/- 35.56 msec (P less than 0.01) and 422.5 +/- 115.36 (P less than 0.01) respectively. As all these values were statistically significant, we consider the photomotographic measurement of ankle reflex as an important aid to the diagnosis of thyroid hormone imbalances.
Aust Fam Physician. 1976 May;5(4):550-9, 561.
A screening test for thyroid function.
The Achilles tendon reflex half relaxation time measurement (ART) has been used by many physicians both as a diagnostic test and for the assessment of progress in thyroid gland malfunction. Reference is made to some results obtained in Melbourne and in other countries using different methods of measurement of the ART for these purposes. In a series of 2064 patients referred to the Shepherd Foundation Centre, the Achilles tendon reflex half relaxation time was measured by means of the SMI Reflexometer and a comparison was made in each case with a laboratory estimation of the T3 resin uptake and T4 total thyroxine iodine and the Free Thyroxine Index (FTI). Reference is made to a survey conducted among referring doctors where opinions were sought as to the clinical usefulness of different tests including the Achilles tendon reflex time measurement.
Probl Endokrinol (Mosk). 1987 May-Jun;33(3):6-9.
[Changes in the duration of the Achilles reflex in euthyroid goiter in children].
[Article in Russian]
Gaĭdina GA, Alekseeva RM, Bobrovskaia TA, Lazareva SP.
Changes in the duration of the Achilles reflex were studied in subclinical disturbances of thyroid function. For this purpose the duration of the Achilles reflex, the levels of T4, T3, iodine protein bound TSH and cholesterol were investigated in children admitted to hospital with the general diagnosis of the “euthyroid goiter”. Clinical and laboratory findings revealed subclinical types of the diffuse toxic goiter, hypothyrosis, chronic thyroiditis, endemic goiter, nodular goiter, pubertal struma and sporadic euthyroid goiter. The aim of the study was to define the diagnostic importance of reflexometry in subclinical disorders of thyroid function and to assess the relationships between metabolic derangements and the duration of the Achilles reflex. Changes in the duration were shown to correspond to disorder of thyroid function. In 76% of the cases reflexometry brought about the correct assessment of the patient’s thyroid status. A significant conformity of the levels of TSH, T3, T4 to the duration of the Achilles reflex was shown.
Med Klin. 1970 Nov 6;65(45):1973-82.
[Validity of Achilles tendon reflex measurement during thyroid gland function disorders].
[Article in German]
Gillich KH, Krüskemper HL, Stendel A.
“A study published in the Journal of Clinical Endocrinology and Metabolism assessed the level of hypothyroidism in 332 female patients based on a clinical score of 14 common signs and symptoms of hypothyroidism and assessments of peripheral thyroid action (tissue thyroid effect). The study found that the clinical score and ankle reflex time correlated well with tissue thyroid effect but the TSH had no correlation with the tissue effect of thyroid hormones (118). The ankle reflex itself had a specificity of 93% (93% of those with slow relaxation phase of the reflexes had tissue hypothyroidism) and a sensitivity of 77% (77% of those with tissue hypothyroidism had a slow relaxation phase of the reflexes) making both the measurement of the reflex speed and clinical assessment a more accurate measurement of tissue thyroid effect than the TSH.” -from How Accurate is TSH Testing?
J Clin Endocrinol Metab. 1997 Mar;82(3):771-6.
Estimation of tissue hypothyroidism by a new clinical score: evaluation of patients with various grades of hypothyroidism and controls.
Zulewski H, Müller B, Exer P, Miserez AR, Staub JJ.
The classical signs and symptoms of hypothyroidism were reevaluated in the light of the modern laboratory tests for thyroid function. We analyzed 332 female subjects: 50 overt hypothyroid patients, 93 with subclinical hypothyroidism (SCH), 67 hypothyroid patients treated with T4, and 189 euthyroid subjects. The clinical score was defined as the sum of the 2 best discriminating signs and symptoms. Beside TSH and thyroid hormones, we measured parameters known to reflect tissue manifestations of hypothyroidism, such as ankle reflex relaxation time and total cholesterol. Classical signs of hypothyroidism were present only in patients with severe overt hypothyroidism with low T3, but were rare or absent in patients with normal T3 but low free T4 or in patients with SCH (normal thyroid hormones but elevated basal TSH; mean scores, 7.8 +/- 2.7 vs. 4.4 +/- 2.2 vs. 3.4 +/- 2.0; P < 0.001). Assessment of euthyroid subjects and T4-treated patients revealed very similar results (mean score, 1.6 +/- 1.6 vs. 2.1 +/- 1.5). In overt hypothyroid patients, the new score showed an excellent correlation with ankle reflex relaxation time and total cholesterol (r = 0.76 and r = 0.60; P < 0.0001), but no correlation with TSH (r = 0.01). The correlation with free T4 was r = -0.52 (P < 0.0004), and that with T3 was r = -0.56 (P < 0.0001). In SCH, the best correlation was found between the new score and free T4 (r = -0.41; P < 0.0001) and TSH (r = 0.35; P < 0.0005). Evaluation of symptoms and signs of hypothyroidism with the new score in addition to thyroid function testing is very useful for the individual assessment of thyroid failure and the monitoring of treatment.