Methods for assessing fatigue level and applications thereof

Abstract

Level of fatigue that accompanies everyday life or a disease can be simply, easily, and quantitatively assessed by obtaining a body fluid from a test subject and measuring the amount of human herpesvirus in the body fluid. Furthermore, the anti-fatigue potency of anti-fatigue substances and anti-fatigue food products can be measured.

1 . A method of assessing fatigue level, comprising assessing fatigue level of a test subject using human herpesvirus amount in a body fluid as an indicator. 
     
     
         2 . The method of assessing fatigue level of  claim 1 , wherein the fatigue level is assessed to be high when the amount of human herpesvirus is high. 
     
     
         3 . The method of assessing fatigue level of  claim 2 , wherein the amount of human herpesvirus is measured as an expression level of a gene of human herpesvirus. 
     
     
         4 . The method of assessing fatigue level of any one of  claims 1  to  3 , wherein the method comprises assessing the test subject to be in a state of overwork due to an accumulation of medium- or long-term acute fatigue arising from everyday life, when the amount of human herpesvirus is high. 
     
     
         5 . The method of assessing fatigue level of any one of  claims 1  to  3 , wherein the method comprises assessing the subject to be in a state of chronic fatigue caused by a disease when the amount of human herpesvirus is high. 
     
     
         6 . The method of assessing fatigue level of any one of  claims 1  to  5 , wherein the fatigue level is the level of
 medium- or long-term fatigue caused by everyday life or fatigue caused by a disease, and 
 mental fatigue and/or complex fatigue. 
 
     
     
         7 . The method of assessing fatigue level of any one of  claims 1  to  6 , wherein the body fluid is at least one fluid selected from blood, saliva, cerebrospinal fluid, and urine. 
     
     
         8 . The method of assessing fatigue level of any one of  claims 1  to  7 , wherein the herpesvirus is at least one virus selected from human herpesvirus 6, human herpesvirus 7, human cytomegalovirus, and Epstein-Barr virus (EBV). 
     
     
         9 . A kit for assessing fatigue level, wherein the kit is for carrying out the method of assessing fatigue level of any one of  claims 1  to  8 . 
     
     
         10 . The kit of  claim 9 , comprising a means for measuring the amount of HHV in a collected body fluid, and which carries an indication that the kit can be used to assess fatigue level of a test subject using human herpesvirus amount in a body fluid as an indicator. 
     
     
         11 . A method of assessing an anti-fatigue effect of a candidate anti-fatigue substance, wherein the method comprises:
 (i) a pre-intake HHV amount-measuring step, which comprises obtaining a body fluid from a test subject before the test subject takes the candidate anti-fatigue substance and measuring the amount of HHV in the body fluid;   (ii) a post-intake HHV amount-measuring step, which comprises obtaining a body fluid from the test subject after the test subject takes the candidate anti-fatigue substance and measuring the amount of HHV in the body fluid;   (iii) a change-in-virus-amount-calculating step, which comprises calculating a change in an HHV amount in a body fluid before and after the intake of the candidate anti-fatigue substance, based on the measurement result on a change in an HHV amount before and after the intake of the candidate anti-fatigue substance, which result is obtained through the pre-intake HHV amount-measuring step of (i) and the post-intake HHV amount-measuring step of (ii); and (iv) an anti-fatigue potency-measuring step, which comprises measuring an in vivo anti-fatigue potency of the candidate anti-fatigue substance based on the change in the HHV amount in the body fluid before and after the intake of the candidate anti-fatigue substance, which change is obtained by the change-in-virus-amount-calculating step of (iii).   
     
     
         12 . A method of assessing an anti-fatigue effect of a candidate anti-fatigue substance, wherein the method comprises:
 (i) an HHV amount-measuring step, which comprises obtaining a body fluid from a test subject who has taken the candidate anti-fatigue substance and from a test subject who has not taken the candidate anti-fatigue substance, and measuring the HHV amount in each body fluid;   (ii) a change-in-virus-amount-calculating step, which comprises calculating a change in an HHV amount in a body fluid depending on whether or not the candidate anti-fatigue substance has been taken, based on the measurement result on a change in an HHV amount depending on whether or not the candidate anti-fatigue substance has been taken, which result is obtained through the process for HHV amount-measuring step of (i), and   (iii) an anti-fatigue potency-measuring step, which comprises measuring an in vivo anti-fatigue potency of the candidate anti-fatigue substance based on the change in the amount of HHV in a body fluid depending on whether or not the candidate substance for an anti-fatigue substance has been taken, which result is obtained through the change-in-virus-amount-calculating step of (ii).   
     
     
         13 . The method of assessing an anti-fatigue effect of  claim 11  or  12 , wherein the method comprises assessing the anti-fatigue effect of the candidate anti-fatigue substance using the method of assessing fatigue level of any one of  claims 1  to  8  or by using the kit for assessing fatigue level of any one of  claims 9  to  10 . 
     
     
         14 . The method of assessing an anti-fatigue effect of a candidate anti-fatigue substance of any one of  claims 11  to  13 , wherein the method is a method of screening for an anti-fatigue substance.