Avoid the inner loop:
T = load('T.mat').T
T = 33133x41 table
       Date       SystemTime    RunTime    CameraPositionX    CameraPositionY    CameraPositionZ    CameraRotationX    CameraRotationY    CameraRotationZ    CameraRotationW     LHType     LHGrabbedObject    LHPositionX    LHPositionY    LHPositionZ    LHRotationX    LHRotationY    LHRotationZ    LHRotationW     RHType      RHGrabbedObject    RHPositionX    RHPositionY    RHPositionZ    RHRotationX    RHRotationY    RHRotationZ    RHRotationW    PupilDiameterLeft    PupilDiameterRight    GazePositionX    GazePositionY    GazePositionZ    FocusInfo    LastRequestedBurger    LastRequestedDrink      OrderNumber       OrderStatus    LastEvent    ManualRegistering    VarName41
    __________    __________    _______    _______________    _______________    _______________    _______________    _______________    _______________    _______________    ________    _______________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    _________    _______________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    _________________    __________________    _____________    _____________    _____________    _________    ___________________    __________________    ________________    ___________    _________    _________________    _________
    15-11-2023       NaT         115.8          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28039        1.3604         0.29594        0.52423       0.088768       -0.067117      -0.84427      RightHand         null           0.076785         1.417         0.25962        0.57927       -0.093584      0.060118       -0.80751            3.52                  3.22                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.84          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28036        1.3603         0.29598        0.52418       0.088865        -0.06694      -0.84431      RightHand         null           0.076829         1.417         0.25964        0.57926       -0.093948      0.060058       -0.80748            3.52                  3.19                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.85          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28035        1.3601         0.29597         0.5239       0.088938       -0.067109      -0.84446      RightHand         null           0.076925         1.417         0.25952        0.57946       -0.094704       0.06007       -0.80724            3.52                  3.22                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.85          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28034          1.36         0.29597        0.52382       0.088891       -0.067402      -0.84449      RightHand         null           0.077037        1.4171         0.25949        0.57962       -0.094954      0.060195        -0.8071            3.52                  3.22                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.86          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28038        1.3599         0.29594        0.52374       0.088781       -0.067576      -0.84454      RightHand         null           0.077072        1.4171          0.2594        0.57976       -0.095229      0.060112       -0.80697            3.53                  3.19                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.87          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28029        1.3599         0.29592        0.52365       0.088697       -0.067646       -0.8446      RightHand         null           0.077094         1.417         0.25934        0.57995       -0.095401      0.060247        -0.8068            3.53                  3.22                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.88          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28026        1.3598         0.29599        0.52374       0.088904       -0.067509      -0.84453      RightHand         null           0.077149         1.417         0.25928        0.58001       -0.095044      0.060641       -0.80677            3.56                  3.21                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.89          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null            -0.2803        1.3598         0.29608        0.52373       0.089089       -0.067429      -0.84452      RightHand         null           0.077182        1.4171         0.25925        0.58007       -0.094702      0.060962       -0.80674            3.56                  3.19                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT         115.9          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28024        1.3598         0.29599        0.52371       0.089113       -0.067484      -0.84453      RightHand         null           0.077223        1.4171         0.25922        0.58002       -0.094394      0.060927       -0.80682            3.56                  3.19                0.06            -0.07               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.91          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28024        1.3598         0.29606        0.52364       0.089165       -0.067725      -0.84455      RightHand         null             0.0772        1.4171         0.25921        0.57998       -0.094445      0.060253       -0.80689            3.51                  3.21                0.03            -0.08               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.92          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28019        1.3595         0.29597        0.52352       0.089106        -0.06791      -0.84462      RightHand         null             0.0773        1.4169         0.25921        0.57996        -0.09467       0.05975       -0.80692            3.53                  3.24               -0.02            -0.08               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.93          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28008        1.3595         0.29597        0.52339       0.089077        -0.06792       -0.8447      RightHand         null           0.077376         1.417         0.25917        0.58005       -0.095062      0.059262       -0.80684            3.48                  3.25               -0.05            -0.08               1           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.94          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28008        1.3595         0.29608        0.52317       0.089007       -0.067806      -0.84485      RightHand         null           0.077386         1.417         0.25912        0.58008       -0.095141      0.059264       -0.80681            3.53                  3.22               -0.06            -0.08            0.99           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.96          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28007        1.3594         0.29613        0.52301       0.088863       -0.067627      -0.84498      RightHand         null           0.077434        1.4171         0.25909        0.58007       -0.095219      0.059544       -0.80679            3.42                  3.19               -0.05            -0.08            0.99           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.97          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.27989        1.3595         0.29614         0.5228       0.088734       -0.067379      -0.84514      RightHand         null           0.077619        1.4172         0.25903        0.57992       -0.095414      0.059866       -0.80685            3.41                   3.2               -0.06            -0.09            0.99           null               ""                     ""            No current order        ""            ""               ""               ""    
    15-11-2023       NaT        115.98          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.27988        1.3594         0.29622        0.52261       0.088784       -0.067391      -0.84525      RightHand         null           0.077741        1.4172         0.25897        0.57993       -0.095369      0.060203       -0.80683            3.39                   3.2               -0.06            -0.09            0.99           null               ""                     ""            No current order        ""            ""               ""               ""    
if width(T)>=37
    V = str2double(string(T{:,37}));
    V(isnan(V)) = 0;
    T = convertvars(T,37,'double');
    T{:,37} = V
end
T = 33133x41 table
       Date       SystemTime    RunTime    CameraPositionX    CameraPositionY    CameraPositionZ    CameraRotationX    CameraRotationY    CameraRotationZ    CameraRotationW     LHType     LHGrabbedObject    LHPositionX    LHPositionY    LHPositionZ    LHRotationX    LHRotationY    LHRotationZ    LHRotationW     RHType      RHGrabbedObject    RHPositionX    RHPositionY    RHPositionZ    RHRotationX    RHRotationY    RHRotationZ    RHRotationW    PupilDiameterLeft    PupilDiameterRight    GazePositionX    GazePositionY    GazePositionZ    FocusInfo    LastRequestedBurger    LastRequestedDrink    OrderNumber    OrderStatus    LastEvent    ManualRegistering    VarName41
    __________    __________    _______    _______________    _______________    _______________    _______________    _______________    _______________    _______________    ________    _______________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    _________    _______________    ___________    ___________    ___________    ___________    ___________    ___________    ___________    _________________    __________________    _____________    _____________    _____________    _________    ___________________    __________________    ___________    ___________    _________    _________________    _________
    15-11-2023       NaT         115.8          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28039        1.3604         0.29594        0.52423       0.088768       -0.067117      -0.84427      RightHand         null           0.076785         1.417         0.25962        0.57927       -0.093584      0.060118       -0.80751            3.52                  3.22                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.84          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28036        1.3603         0.29598        0.52418       0.088865        -0.06694      -0.84431      RightHand         null           0.076829         1.417         0.25964        0.57926       -0.093948      0.060058       -0.80748            3.52                  3.19                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.85          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28035        1.3601         0.29597         0.5239       0.088938       -0.067109      -0.84446      RightHand         null           0.076925         1.417         0.25952        0.57946       -0.094704       0.06007       -0.80724            3.52                  3.22                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.85          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28034          1.36         0.29597        0.52382       0.088891       -0.067402      -0.84449      RightHand         null           0.077037        1.4171         0.25949        0.57962       -0.094954      0.060195        -0.8071            3.52                  3.22                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.86          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28038        1.3599         0.29594        0.52374       0.088781       -0.067576      -0.84454      RightHand         null           0.077072        1.4171          0.2594        0.57976       -0.095229      0.060112       -0.80697            3.53                  3.19                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.87          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28029        1.3599         0.29592        0.52365       0.088697       -0.067646       -0.8446      RightHand         null           0.077094         1.417         0.25934        0.57995       -0.095401      0.060247        -0.8068            3.53                  3.22                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.88          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28026        1.3598         0.29599        0.52374       0.088904       -0.067509      -0.84453      RightHand         null           0.077149         1.417         0.25928        0.58001       -0.095044      0.060641       -0.80677            3.56                  3.21                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.89          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null            -0.2803        1.3598         0.29608        0.52373       0.089089       -0.067429      -0.84452      RightHand         null           0.077182        1.4171         0.25925        0.58007       -0.094702      0.060962       -0.80674            3.56                  3.19                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT         115.9          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28024        1.3598         0.29599        0.52371       0.089113       -0.067484      -0.84453      RightHand         null           0.077223        1.4171         0.25922        0.58002       -0.094394      0.060927       -0.80682            3.56                  3.19                0.06            -0.07               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.91          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28024        1.3598         0.29606        0.52364       0.089165       -0.067725      -0.84455      RightHand         null             0.0772        1.4171         0.25921        0.57998       -0.094445      0.060253       -0.80689            3.51                  3.21                0.03            -0.08               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.92          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28019        1.3595         0.29597        0.52352       0.089106        -0.06791      -0.84462      RightHand         null             0.0773        1.4169         0.25921        0.57996        -0.09467       0.05975       -0.80692            3.53                  3.24               -0.02            -0.08               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.93          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28008        1.3595         0.29597        0.52339       0.089077        -0.06792       -0.8447      RightHand         null           0.077376         1.417         0.25917        0.58005       -0.095062      0.059262       -0.80684            3.48                  3.25               -0.05            -0.08               1           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.94          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28008        1.3595         0.29608        0.52317       0.089007       -0.067806      -0.84485      RightHand         null           0.077386         1.417         0.25912        0.58008       -0.095141      0.059264       -0.80681            3.53                  3.22               -0.06            -0.08            0.99           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.96          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.28007        1.3594         0.29613        0.52301       0.088863       -0.067627      -0.84498      RightHand         null           0.077434        1.4171         0.25909        0.58007       -0.095219      0.059544       -0.80679            3.42                  3.19               -0.05            -0.08            0.99           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.97          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.27989        1.3595         0.29614         0.5228       0.088734       -0.067379      -0.84514      RightHand         null           0.077619        1.4172         0.25903        0.57992       -0.095414      0.059866       -0.80685            3.41                   3.2               -0.06            -0.09            0.99           null               ""                     ""                 0             ""            ""               ""               ""    
    15-11-2023       NaT        115.98          -0.11              1.62               0.01               -0.14              -0.01              -0.05              -0.99         LeftHand         null           -0.27988        1.3594         0.29622        0.52261       0.088784       -0.067391      -0.84525      RightHand         null           0.077741        1.4172         0.25897        0.57993       -0.095369      0.060203       -0.80683            3.39                   3.2               -0.06            -0.09            0.99           null               ""                     ""                 0             ""            ""               ""               ""    
Is the column position reliable? Perhaps you should use the column name and/or the column type.
Note that you might also be able to modify the file import options to import that column directly as numeric.


