Table 5.
Local cold water immersion laboratory studies.
| Reference | Study Sample | Habituation Length | Habituation Temperature | Cold Testing Procedure | Results/Findings |
|---|---|---|---|---|---|
| Eagen [78] | 6 M airmen | 125 consecutive days, 10 min middle finger immersion 6x per day | 0°C | Identical immersion post testing on day 126,127, and 128 | Post habituation, finger temperature of the control contralateral finger during immersion was similar to habituated finger but maximum pain was ↓ for the habituated finger vs control; habituated finger temperature of immersed group was ↑ than that of a separate control group |
| LeBlanc [81] | 16 M | Two groups 8 M each: (1) L hand cold water exposure 2x/day for 5 consecutive days for 4 weeks; (2) cold water immersion of L hand + mental arithmetic | Group (1): 4°C Group (2): 4°C |
Pre and post testing consisting of: Test I: immersion of L hand in 4°C water for 2.5 min Test II: Mental arithmetic test Test III: cold water immersion of L hand + mental arithmetic Test IV (only added post): immersion of R hand in 4°C water for 2.5 min |
Those in group 2 (cold water immersion + mental arithmetic), did not adapt to the cold water test alone (↔ in blood pressure), only the combination of cold water immersion + mental arithmetic (↓ blood pressure) following habituation; ↓ BP and pain estimation response to cold in one hand did not confer the same adaptation to the opposite hand, rather it appeared to sensitize the response |
| Zbrozyna [82] | 7 M, 4 F | Cold water immersion of one foot for 60 sec 7x/day for 6 days; rewarming bath between intervals | 4°C water; 36°C rewarming bath |
Longitudinal passive (time-focused) observation | After repeated cold water immersions, ↓ in reactive muscle vasodilation (noticeable even after a single session of immersion) and BP (most significant around immersion day 4) to same stimulus |
| Leftheriotis [77] | 10 M Caucasians; 5 M locally cold-acclimated, 5 M were non-acclimated | Daily immersion of the R hand and forearm in a stirred water bath for 20 min for 30 days | 5°C water | Pre and post testing consisting of three tests performed in both 25°C air and after 5 min hand and forearm cooling in 5°C: (1) peak blood flow following ischemia, (2) peak blood flow following exercise, (3) peak blood flow following ischemia and exercise combined | After repeated cold exposure, lesser ↓ in skin temperature; peak blood flow following ischemia and ischemia+exercise in the finger and forearm was ↓ in the cooled condition only in those who were cold-acclimated; forearm peak blood flow following exercise was ↓ in the cooled condition only in the cold-acclimated males indicating muscle blood flow was also ↓; overall, cold-acclimated males showed ↓ vasodilatory responses only when exposed to cold |
| Carman [83] | 38 M & F | 9 days of cryokinetic treatments (5 cold immersions interspersed with 3-min of exercise) to R ankle + 1 day to L ankle; cold water immersion included 1 20-min immersion followed by 4, 5-min immersions | 1° or 5°C water; wearing toe caps | Longitudinal passive (time-focused) observation; Days 9 & 10 R ankle treated with opposite temperature and L ankle was treated with habituation temperature | From combined 1 and 5°C data: Sharp ↓ in cold pain from days 1–5, but no difference from 5–8 days; instep was the most frequent location of pain for the first 3 days and the choice of “no specific location” ↑ steadily from day 2–8; on days 9 & 10 pain in the L limb was ↑ than that at the end of the R limb habituation but ↔ to day 1 of habituation indicating non-adaptation transference; R limb immersion in a lower temperature resulted in ↑ pain than that perceived on day 8 indicating temperature adaptation specificity |
| Savourey [80] | 8 M (euthyroid) | Standing ice water immersion of lower limbs up to 20 cm above the knees 2x/day, 5 days/wk for 1 month; duration of immersion was to tolerance (~5 min at the start and ~60 min by the end) | 0–5°C | Pre and post testing using Standard Cold Air Test (SCAT): 1°C air exposure for 2 hrs, nude, at rest | After acclimation, slightly ↓ TT3 both before (−18%) and after (−11.7%) correction for change in plasma volume, ↓ Tc suggests a hypothermic general cold adaptation |
| Savourey [79] | 8 M (euthyroid) | Ice water immersion of lower limbs up to 20 cm above the knees 2x/day, 5 days/wk for 1 month; duration of immersion was to tolerance (~5 min at the start and ~60 min by the end); 40 total immersions | 0-5°C; wearing bathing suit, shirt and waistcoat to prevent shivering | Pre and post testing using cold foot test (CFT; 5°C water immersion of R foot up to the knee for 5 min) + Standard Cold Air Test (SCAT; 1°C air exposure for 2 hrs, nude, at rest) | ↑ Tsk of lower limbs and ↓ related pain during CFT and ↓ Trec and mean Tsk; ↔ metabolic heat production or lower limb skin temperatures during SCAT; ↓ plasma NE over the course of habituation but ↑ in NE during SCAT after habituation; post cold acclimation: ↑ FT3 and slight ↑ TT3 from pre-control vs 40th immersion but ↔ TT4, FT4, and TSH (termed “T3 polar syndrome”) |
| Tipton [99] | 13 M; 8 habituation, 4 CON | 6 3-min head-out immersions over 3 days (2x/day) | 15°C; wearing swimming trunks | Pre and post testing: 3-min head-out 10°C cold water immersion wearing swimming trunks | After habituation exposure at 15°C, respiratory rate, inspiratory minute volume, and HR ↓ over the first 30 sec (as well as the rest of the 3-min immersion) of exposure in both 15 and 10°C water; habituation can be achieved with warmer water than that for which adaptation is required |
| Kolev [147] | 5 M, 5 F | 10 cold water immersions of one foot for 30 sec with inter-stimulus intervals ranging from 3.5–5 min, rewarmed during withdrawal intervals vs. internal caloric stimulation |
5°C for cold water immersion, 37°C rewarm | Longitudinal passive (time-focused) observation | With repeat external cold water foot immersion, ↓ in the red cell flux in the index finger indicating a habituation of the cold microcirculatory reflex (significant ↓ after 7th stimulation); ↔ in Tsk of the index finger following the 10 immersions |
| Geurts [148] | 7 M, 4 F Caucasian | Left hand cold water immersion for 30 min, 5d/wk for 2 wks | 8°C water | Pre and post testing: neuromuscular function, blood markers, thermal sensation, and temperature responses of both L and R hands assessed in both thermoneutral (~24°C) and cold (8°C) conditions | From pre to post in R vs L hand ↔ in minimum index finger temperature, Tc, HR, NE, E, NO Endothelin-1, or hand temperature; thermal comfort after 30 min of cold water immersion ↑ in the hand repeatedly exposed to cold, but not in the non-exposed hand |
| Daanen (76) | 9 M, 7 F | Right hand and foot simultaneous immersion 30 min daily for 15 consecutive days | 8°C water | Longitudinal observation daily of pain, tactile sensitivity, and skin temperatures of right (trained) hand and foot; pre and post training immersion testing of both right and left (untrained) hands and feet | From first to last immersion, mean toe temperature of the trained foot ↑, but mean finger temperature and number of CIVD reactions ↓ (~30%) in trained hand; no significant differences seen in the untrained limbs; pain ↓ as a function of time and tactile sensitivity ↓ alongside skin temperature; this combination of adaptation may lead to an increased risk of finger cold injuries |
| Simpson [84] | 9 M, 8 F | Single hand cold water immersion to tolerance to a maximum immersion duration of 180 s at baseline and every 5th and 7th day for 3 weeks (total of 7 immersions) in control vs. sleep restricted groups | 2–3°C water | Longitudinal passive (time-focused) observation | In the control sleep group, cold pain tolerance time ↑ by 24 s from baseline to week 3, while in the sleep restricted group cold pain tolerance ↑ by 9.5 s |