How do I keep it from repeatedly regenerating?

This is the code for a stamina bar in my game. It is supposed to regenerate after the player either runs out of stamina, or stops sprinting. It keeps regenerating while sprinting though. It is in a LocalScript under the StarterGui.

local StaminaBar = script.Parent
local Stamina = StaminaBar:WaitForChild("Stamina")
local Frame = StaminaBar.Parent
local Warning = Frame:WaitForChild("Warning")
local InputService = game:GetService("UserInputService")
local Player = game.Players.LocalPlayer
local Keys = {}

InputService.InputBegan:connect(function(Input)
    Keys[Input.KeyCode.Name] = true
    while Keys.Q and Stamina.Value > 0 do
        Player.Character.Humanoid.WalkSpeed = 28
        wait(0.01)
        Stamina.Value = Stamina.Value - 1
        StaminaBar.Size = StaminaBar.Size - UDim2.new(0.01, 0, 0, 0)
    end
end)

InputService.InputEnded:connect(function(Input)
    Keys[Input.KeyCode.Name] = false
    if not Keys.Q then
        Player.Character.Humanoid.WalkSpeed = 16
        wait(4)
        Warning:TweenPosition(UDim2.new(0.2, 0, 0, 0), "Out", "Quad", 0.25, true, nil)
        StaminaBar:TweenSize(UDim2.new(1, 0, 1, 0), "Out", "Quad", 0.5, true, nil)
        Stamina.Value = 100
    end
end)

Stamina.Changed:connect(function()
    if Stamina.Value < 40 then
        Warning:TweenPosition(UDim2.new(0.2, 0, -1.3, 0), "Out", "Quad", 0.25, true, nil)
    end
end)