Can the inner eye canthus temperature be used as an alternative method to measure core temperature in sleep-deprived individuals?

Core temperature is used in several situations, including studies on biological rhythms and circadian markers of physical performance. Measuring the inner eye canthus (Tco) temperature is a method proposed to identify core temperature, but it has shown little concordance in physical exercise situations and has not yet been used in studies with measurements taken throughout the day. The objective of this study was to compare the measurements and daily behavior of Tco obtained by infrared thermography with rectal temperature (Tre) during a prolonged waking protocol. Eleven male individuals participated in the study, who remained in the laboratory for at least 38 h using an actigraph to determine the wakefulness time and were monitored during the entire period. The Tre and Tco measurements were performed every 3 h. The ANOVA was used for repeated measurements followed by Bonferroni's post-hoc test to find the limits of concordance/proximity, while the Bland and Altman method and the Intraclass Correlation Coefficient were used to establish the reliability between the pairs. The significance level adopted was p < 0.05. The results demonstrate significant differences, low levels of concordance and unsatisfactory reliability levels between Tco and Tre at all 13 analyzed moments, in addition to not showing measurement reliability when all data are used together with the 143 temperature measurements. Daily behavior analysis shows moments with similar behavior with an increase in Tco and Tre, but at other times the behavior was the opposite, with a decrease in one measurement and an increase in the other. Based on the results presented, it is not recommended to use the inner eye canthus temperature as a substitute for rectal temperature for measuring core temperature at different times of the day or in sleep-deprived individuals.

Daily rhythm of skin temperature of women evaluated by infrared thermal imaging.

It is well known that skin temperature varies due to circadian rhythm. Although there is information available for men, little is known about women's circadian rhythm in the analysis of skin temperature (Tsk) using infrared thermography. The objective of this study is to identify Tsk variations on different body regions in women through infrared thermography during the day. The sample consisted of 20 female (mean age of 20.5 ± 1.3 years, body weight of 62.2 ± 9.2kg and height of 165.0 ± 4.7cm). Oneway ANOVA for repeated measures, and Cosinor analysis was used to determine the MESOR, amplitude and acrophase of Tsk. The regions of the forearm, upper arm and anterior and posterior legs in the lower limbs, as well as the chest and scapulae in the upper limbs showed higher variability throughout the day. In general, distal regions had lower values compared with the central regions, and the pectoral region had the lowest standard deviation values. Tsk of the analyzed regions at different times show significant differences between periods of the day in young active women, showing the minimum absolute values for both Tsk in the early morning. These results highlight the need to consider the time of day when analyzing women's skin temperature. Future studies should report the time of day when the images were collected, as well as consider the circadian rhythm when making comparisons.

Daily oscillations of skin temperature in military personnel using thermography.

INTRODUCTION: The human body makes many physiological adjustments throughout the day, including adjustments to body temperature. The purpose of this study was to determine oscillations in the skin temperature (Tsk-1-Tsk-25) at 25 body regions of interest (ROIs) over 1 day using infrared thermography. METHODS: Tsk values of 31 male (age 22.9±3.0 years) Brazilian Air Force members were evaluated from five thermograms collected at 7, 11, 15, 19 and 23 h (Tsk7,11,15,19,23) by a Fluke imager. We applied one-way analysis of variance for repeated measures for the different times of the day and Tukey's post hoc test to determine significant Tsk differences between ROIs (α=0.05), and the cosinor analysis was used to determine the midline estimating statistic of rhythm, amplitude and acrophase of Tsk during the 24 h period. RESULTS: The anterior hands showed the greatest Tsk variations throughout the day. In the lower limbs, scapula, abdomen, chest and lower back, Tsk-11, Tsk-15, Tsk-19 and Tsk-23 were significantly different (p<0.05) from Tsk-7. The lowest Tsk values were obtained in the early morning, with increases in the afternoon and levelling after 15:00. CONCLUSIONS: The Tsk at all ROIs and the averaged Tsk showed oscillations throughout the day, with the lowest values in the early morning (07:00). Temperature fluctuations depended on the specific ROI, with thermal stabilisation in some regions in the afternoon and a central upward trend throughout the day in the hands.

Thermal body patterns for healthy Brazilian adults (male and female).

The aim of this study was to establish the skin temperature (Tsk) thermal profile for the Brazilian population and to compare the differences between female and male Brazilian adults. A total of 117 female and 103 male were examined with a thermographic camera. The Tsk of 24 body regions of interest (ROI) were recorded and analyzed. Male Tsk results were compared to female and 10 ROI were evaluated with respect to the opposite side of the body (right vs. left) to identify the existence of significant contralateral Tsk differences (ΔTsk). When compared right to left, the largest contralateral ΔTsk was 0.3°C. The female vs. male analysis yielded significant differences (p<0.05) in 13 of the 24 ROI. Thigh regions, both ventral and dorsal, had the highest ΔTsk by sex (≈1.0°C). Tsk percentile below P5 or P10 and over P90 or P95 may be used to characterize hypothermia and hyperthermia states, respectively. Thermal patterns and Tsk tables were established for Brazilian adult men and women for each ROI. There is a low Tsk variation between sides of the body and gender differences were only significant for some ROIs.

Can IGF-1 Serum Levels Really be Changed by Acute Physical Exercise? A Systematic Review and Meta-Analysis.

BACKGROUND: Physical exercise plays an important role in metabolic health, especially in the insulin-like growth factor-1 (IGF-1) system. The objective of this study was to perform a systematic review and meta-analysis to evaluate the effects of a single endurance and resistance exercise session on IGF-1 serum. METHODS: The systematic review was performed in SPORTDiscus, MEDLINE, PubMed, and Google Scholar databases. All analyses are based on random-effect models. The study identified 249 records of which 21 were included. RESULTS: There was an effect of endurance exercise on total IGF-1 (P = .01), but not for free IGF-1 (P = .36). Resistance exercise similarly only affected total IGF-1 (P = .003) and not free IGF-1 (P = .37). The effect size indicated that total IGF-1 is more affected (ES = 0.81) by endurance than by resistance exercise (ES = 0.46). The present study showed that IGF-1 serum concentrations are altered by exercise type, but in conditions which are not well-defined. CONCLUSIONS: The systematic review and meta-analysis suggest that there is no determinant in serum IGF-1 changes for the exercise load characteristic. Therefore, physical exercise may be an alternative treatment to control changes in IGF-1 metabolism and blood concentration.

Influência da privação de sono no desempenho de atletas: uma revisão sistemática / The influence of sleep deprivation on athletes' performance: a systematic review

RESUMO O sono é uma estratégia importante para a recuperação de atletas e o estado de privação de sono pode influenciar a performance esportiva. O objetivo do estudo foi realizar uma revisão sistemática de literatura para analisar a influência da privação de sono no desempenho físico e esportivo de atletas. A pesquisa foi realizada a partir das bases de dados eletrônicas PubMed, Scopus, SportDiscus e Scielo. Foram selecionados artigos originais publicados escritos no idioma inglês ou português. Após a busca nas bases de dados foram encontrados 143 artigos sendo 45 no PubMed, 72 no Scopus, 1 no Scielo e 25 no SportDiscus. Posteriormente a análise dos artigos, 8 artigos foram incluídos no presente estudo de acordo com os critérios de inclusão. Após análise dos 8 artigos incluídos na revisão, concluiu-se que a privação de sono influenciou negativamente no desempenho físico e esportivo em 5 dos artigos analisados. Além disso, constatou-se que o período de privação de sono é determinante para o desempenho dos atletas nas tarefas esportivas.

ABSTRACT Sleeping is an important strategy for athletes' recovery and the state of sleep deprivation can influence the sports performance.The objective of the study was to carry out a systematic literature review in order to analyze the influence of sleep deprivation on the physical and athletic performance of athletes. The study was carried out from the electronic databases PubMed, Scopus, SportDiscus and Scielo. We selected original articles published and written in English or Portuguese were selected. After the search in the databases we found 143 articles were found being 45 from PubMed, 72 from Scopus, 1 from Scielo and 25 from SportDiscus. After the full analysis of the articles, only 8 of them articles were included in the present study according to the inclusion criteria. After analyzing the 8 articles included in the present review it was concluded that sleep deprivation negatively influenced physical and sports performance in 5 of the analyzed articles. In addition, it was found that the sleep deprivation period is determinant for athletes' performance in sports tasks.

Effects of cumulative school soccer matches separated by 24-h or 48-h intervals on physical recovery status of U-19 players / Efeitos de partidas consecutivas de futebol escolar com intervalos de 24 e 48 horas no estado de recuperação física de jogadores Sub-19

Abstract This study aimed to evaluate the effects of cumulative school soccer matches separated by 24-h or 48-h intervals on the recovery status of U-19 players. Thirty-four school athletes (17.6 ± 1.1 years) who played in an U-19 school soccer competition (composed of one group with four teams and another group with three teams, followed by semifinals and final) were examined before three matches, which lasted 70 min. Seventeen athletes had a 24-h rest interval between each match (GGG group), while 18 athletes had a 48-h rest interval between the second and third matches (GG48hG group). Total Quality Recovery, countermovement jump, 10-m sprint, and maximum lumbar isometric strength were measured. The internal load of each match was calculated by the product of the session Rating of Perceived Exertion and match time. There was a 22% reduction in Total Quality Recovery (p< 0.001) and 12% in 10-m sprint performance (p< 0.001) before the third match in the GGG group, while the GG48hG group showed no changes for the same variables (p> 0.05). The countermovement jump decreased before the second match in both groups (GGG= 12% and GG48hG= 10%; p< 0.001), with no difference between groups (p> 0.05). In addition, both groups showed no changes in the isometric strength or the internal load match over the games (p> 0.05). Despite not providing complete muscle recovery, a 48-h interval between the second and third matches seems to have minimized the reduction of muscle performance due to consecutive matches.

Resumo Este estudo teve como objetivo avaliar os efeitos de partidas consecutivas de futebol escolar com intervalos de 24 e 48 horas no estado de recuperação física de jogadores Sub-19. Foram avaliados 35 homens (17,6±1,1 anos) atletas escolares sub-19. Durante a competição, foram realizados três jogos de 70-min de duração. Dezessete atletas tiveram intervalo de 24h entre cada jogo (grupo GGG). Dezoito atletas tiveram intervalo de 48 h entre o 2º e o 3º jogo (grupo GG48hG). Antes de cada jogo foram medidas a Qualidade Total de Recuperação, altura do salto com contra movimento, velocidade no sprint de 10-m, e força máxima isométrica lombar máxima. A carga interna do jogo foi calculada pelo produto da percepção subjetiva do esforço da sessão e tempo de cada jogo. Houve uma redução de 22% na qualidade total de recuperação (p <0,001) e de 12% no desempenho de sprint de 10 m (p <0,001) antes da terceira partida no grupo GGG, enquanto o grupo GG48hG não apresentou alterações para as mesmas variáveis (p> 0,05). O salto com contra movimento diminuiu antes da segunda partida em ambos os grupos (GGG = 12% e GG48hG = 10%; p <0,001), sem diferença entre os grupos (p> 0,05). Em adição, ambos os grupos não apresentaram alterações na força isométrica e na carga interna ao longo dos jogos (p> 0,05). Apesar de não proporcionar uma completa recuperação muscular, 48 h de intervalo entre o segundo e o terceiro jogo parece ter minimizado o efeito de jogos consecutivos na redução do desempenho.

Measuring skin temperature before, during and after exercise: a comparison of thermocouples and infrared thermography.

Measuring skin temperature (TSK) provides important information about the complex thermal control system and could be interesting when carrying out studies about thermoregulation. The most common method to record TSK involves thermocouples at specific locations; however, the use of infrared thermal imaging (IRT) has increased. The two methods use different physical processes to measure TSK, and each has advantages and disadvantages. Therefore, the objective of this study was to compare the mean skin temperature (MTSK) measurements using thermocouples and IRT in three different situations: pre-exercise, exercise and post-exercise. Analysis of the residual scores in Bland-Altman plots showed poor agreement between the MTSK obtained using thermocouples and those using IRT. The averaged error was -0.75 °C during pre-exercise, 1.22 °C during exercise and -1.16 °C during post-exercise, and the reliability between the methods was low in the pre- (ICC = 0.75 [0.12 to 0.93]), during (ICC = 0.49 [-0.80 to 0.85]) and post-exercise (ICC = 0.35 [-1.22 to 0.81] conditions. Thus, there is poor correlation between the values of MTSK measured by thermocouples and IRT pre-exercise, exercise and post-exercise, and low reliability between the two forms of measurement.

[Polar S810 as an alternative resource to the use of the electrocardiogram in the 4-second exercise test]. / Polar S810 como recurso alternativo ao eletrocardiograma no teste de exercício de 4 segundos.

BACKGROUND: The 4-second exercise test (T4s) evaluates the cardiac vagal tone during the initial heart rate (HR) transient at sudden dynamic exercise, through the identification of the cardiac vagal index (CVI) obtained from the electrocardiogram (ECG). OBJECTIVE: To evaluate the use of the Polar S810 heart rate monitor (HRM) as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. METHODS: In this study, 49 male individuals (25 +/- 20 years, 176 +/-12 cm, 74 +/- 6 kg) underwent the 4-second exercise test. The RR intervals were recorded simultaneously by ECG and HRM. We calculated the mean and the standard deviation of the last RR interval of the pre-exercise period, or of the first RR interval of the exercise period, whichever was longer (RRB), of the shortest RR interval of the exercise period (RRC), and of the CVI obtained by ECG and HRM. We used the Student t-test for dependent samples (p < or 0.05) to test the significance of the differences between means. To identify the correlation between the ECG and the HRM, we used the linear regression to calculate the Pearson's correlation coefficient and the strategy proposed by Bland and Altman. RESULTS: Linear regression showed r(2) of 0.9999 for RRB, 0.9997 for RRC, and 0.9996 for CVI. Bland e Altman strategy presented standard deviation of 0.92 ms for RRB, 0.86 ms for RRC, and 0.002 for CVI. CONCLUSION: Polar S810 HRM was more efficient in the application of T4s compared to the ECG.

Polar S810 como recurso alternativo ao eletrocardiograma no teste de exercício de 4 segundos / Polar S810 as an alternative resource to the use of the electrocardiogram in the 4-second exercise test

FUNDAMENTO: O teste de exercício de 4 segundos (T4s) avalia o tônus vagal cardíaco durante o transiente inicial da frequência cardíaca (FC), em exercício dinâmico súbito, por meio da identificação do índice vagal cardíaco (IVC) obtido a partir do eletrocardiograma (ECG). OBJETIVO: Testar a utilização do monitor de frequência cardíaca (MFC) Polar S810 como recurso alternativo ao ECG na aplicação do T4s. MÉTODOS: Neste trabalho, 49 indivíduos do sexo masculino (25 ± 20 anos, 176 ± 12 cm, 74 ± 6 kg) realizaram o T4s. Os intervalos RR foram registrados simultaneamente por ECG e MFC. Calcularam-se média e desvio padrão do último intervalo RR do período pré-exercício ou o primeiro do período de exercício, aquele que for mais longo (RRB), do mais curto intervalo RR do período de exercício (RRC) e do IVC obtidos por ECG e MFC. Utilizou-se o teste t de Student para amostras dependentes (p < 0,05) para testar a significância das diferenças entre as médias. Para identificar a concordância entre o ECG e o MFC, utilizou-se a regressão linear, com cálculo do coeficiente de correlação de Pearson e a estratégia proposta por Bland e Altman. RESULTADOS: A regressão linear apresentou r² de 0,9999 para o RRB, 0,9997 para o RRC e 0,9996 para o IVC. A estratégia de Bland e Altman apresentou desvio padrão de 0,92 ms para o RRB, 0,86 ms para o RRC e 0,002 para o IVC. CONCLUSÃO: O MFC Polar S810 se mostrou eficiente na aplicação do T4s quando comparado ao ECG.

BACKGROUND: The 4-second exercise test (T4s) evaluates the cardiac vagal tone during the initial heart rate (HR) transient at sudden dynamic exercise, through the identification of the cardiac vagal index (CVI) obtained from the electrocardiogram (ECG). OBJECTIVE: To evaluate the use of the Polar S810 heart rate monitor (HRM) as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. METHODS: In this study, 49 male individuals (25 ± 20 years, 176 ±12 cm, 74 ± 6 kg) underwent the 4-second exercise test. The RR intervals were recorded simultaneously by ECG and HRM. We calculated the mean and the standard deviation of the last RR interval of the pre-exercise period, or of the first RR interval of the exercise period, whichever was longer (RRB), of the shortest RR interval of the exercise period (RRC), and of the CVI obtained by ECG and HRM. We used the Student t-test for dependent samples (p < 0.05) to test the significance of the differences between means. To identify the correlation between the ECG and the HRM, we used the linear regression to calculate the Pearson's correlation coefficient and the strategy proposed by Bland and Altman. RESULTS: Linear regression showed r² of 0.9999 for RRB, 0.9997 for RRC, and 0.9996 for CVI. Bland e Altman strategy presented standard deviation of 0.92 ms for RRB, 0.86 ms for RRC, and 0.002 for CVI. CONCLUSION: Polar S810 HRM was more efficient in the application of T4s compared to the ECG.