diff --git a/lua/auto-dark-mode/health.lua b/lua/auto-dark-mode/health.lua
index b42d832..565c720 100644
--- a/lua/auto-dark-mode/health.lua
+++ b/lua/auto-dark-mode/health.lua
@@ -1,14 +1,20 @@
 local M = {}
 
+local uv = vim.uv or vim.loop
+
 local adm = require("auto-dark-mode")
+local interval = require("auto-dark-mode.interval")
 
 M.benchmark = function(iterations)
 	local results = {}
 
 	for _ = 1, iterations do
-		local _start = vim.uv.hrtime()
-		vim.system(adm.state.query_command, { text = true }):wait()
-		local _end = vim.uv.hrtime()
+		local _start = uv.hrtime()
+		-- by using an empty function, parsing the response is measured, but
+		-- actually syncing the vim theme isn't performed
+		interval.poll_dark_mode(function() end)
+		local _end = uv.hrtime()
+
 		table.insert(results, (_end - _start) / 1000000)
 	end
 
@@ -24,37 +30,45 @@ M.benchmark = function(iterations)
 	return { avg = sum / #results, max = max, min = min }
 end
 
+-- support for neovim < 0.9.0
+local H = vim.health
+local health = {}
+health.start = H.start or H.report_start
+health.ok = H.ok or H.report_ok
+health.info = H.info or H.report_info
+health.error = H.error or H.report_error
+
 M.check = function()
-	vim.health.start("auto-dark-mode.nvim")
+	health.start("auto-dark-mode.nvim")
 
 	if adm.state.setup_correct then
-		vim.health.ok("Setup is correct")
+		health.ok("Setup is correct")
 	else
-		vim.health.error("Setup is incorrect")
+		health.error("Setup is incorrect")
 	end
 
-	vim.health.info("Detected operating system: " .. adm.state.system)
-	vim.health.info("Using query command: `" .. table.concat(adm.state.query_command, " ") .. "`")
+	health.info(string.format("Detected operating system: %s", adm.state.system))
+	health.info(string.format("Using query command: `%s`", table.concat(adm.state.query_command, " ")))
 
 	local benchmark = M.benchmark(30)
-	vim.health.info(
+	health.info(
 		string.format("Benchmark: %.2fms avg / %.2fms min / %.2fms max", benchmark.avg, benchmark.min, benchmark.max)
 	)
 
-	local interval = adm.options.update_interval
-	local ratio = interval / benchmark.avg
-	local info = string.format("Update interval (%dms) is %.2fx the average query time", interval, ratio)
+	local update_interval = adm.options.update_interval
+	local ratio = update_interval / benchmark.avg
+	local info = string.format("Update interval (%dms) is %.2fx the average query time", update_interval, ratio)
 	local error = string.format(
 		"Update interval (%dms) seems too short compared to current benchmarks, consider increasing it",
-		interval
+		update_interval
 	)
 
 	if ratio > 30 then
-		vim.health.ok(info)
+		health.ok(info)
 	elseif ratio > 5 then
-		vim.health.warn(info)
+		health.warn(info)
 	else
-		vim.health.error(error)
+		health.error(error)
 	end
 end
 
diff --git a/lua/auto-dark-mode/init.lua b/lua/auto-dark-mode/init.lua
index 607bae4..eb564d2 100644
--- a/lua/auto-dark-mode/init.lua
+++ b/lua/auto-dark-mode/init.lua
@@ -1,10 +1,17 @@
 local M = {}
 
+local uv = vim.uv or vim.loop
+
 ---@alias Appearance "light" | "dark"
 ---@alias DetectedOS "Linux" | "Darwin" | "Windows_NT" | "WSL"
 
 ---@class AutoDarkModeOptions
 local default_options = {
+	-- Optional. Fallback theme to use if the system theme can't be detected.
+	-- Useful for linux and environments without a desktop manager.
+	---@type Appearance?
+	fallback = "dark",
+
 	-- Optional. If not provided, `vim.api.nvim_set_option_value('background', 'dark', {})` will be used.
 	---@type fun(): nil | nil
 	set_dark_mode = function()
@@ -17,21 +24,13 @@ local default_options = {
 		vim.api.nvim_set_option_value("background", "light", {})
 	end,
 
-	-- Every `update_interval` milliseconds a theme check will be performed.
+	-- Optional. Specifies the `update_interval` milliseconds a theme check will be performed.
 	---@type number?
 	update_interval = 3000,
-
-	-- Optional. Fallback theme to use if the system theme can't be detected.
-	-- Useful for linux and environments without a desktop manager.
-	---@type Appearance
-	fallback = "dark",
 }
 
 local function validate_options(options)
 	vim.validate({
-		set_dark_mode = { options.set_dark_mode, "function" },
-		set_light_mode = { options.set_light_mode, "function" },
-		update_interval = { options.update_interval, "number" },
 		fallback = {
 			options.fallback,
 			function(opt)
@@ -39,6 +38,9 @@ local function validate_options(options)
 			end,
 			"`fallback` must be either 'light' or 'dark'",
 		},
+		set_dark_mode = { options.set_dark_mode, "function" },
+		set_light_mode = { options.set_light_mode, "function" },
+		update_interval = { options.update_interval, "number" },
 	})
 	M.state.setup_correct = true
 end
@@ -53,21 +55,11 @@ M.state = {
 	query_command = {},
 }
 
--- map the vim.loop functions to vim.uv if available
-local getuid = vim.uv.getuid or vim.loop.getuid
-
 M.init = function()
-	local os_uname = vim.uv.os_uname() or vim.loop.os_uname()
+	local os_uname = uv.os_uname()
 
 	if string.match(os_uname.release, "WSL") then
 		M.state.system = "WSL"
-		if not vim.fn.executable("reg.exe") then
-			error([[
-			auto-dark-mode.nvim:
-			`reg.exe` is not available. To support syncing with the host system,
-			this plugin relies on `reg.exe` being on the `$PATH`.
-			]])
-		end
 	else
 		M.state.system = os_uname.sysname
 	end
@@ -77,9 +69,9 @@ M.init = function()
 	elseif M.state.system == "Linux" then
 		if not vim.fn.executable("dbus-send") then
 			error([[
-			auto-dark-mode.nvim:
-			`dbus-send` is not available. The Linux implementation of
-			auto-dark-mode.nvim relies on `dbus-send` being on the `$PATH`.
+        auto-dark-mode.nvim:
+        `dbus-send` is not available. The Linux implementation of
+        auto-dark-mode.nvim relies on `dbus-send` being on the `$PATH`.
 			]])
 		end
 
@@ -95,8 +87,28 @@ M.init = function()
 			"string:color-scheme",
 		}
 	elseif M.state.system == "Windows_NT" or M.state.system == "WSL" then
+		local reg = "reg.exe"
+
+		-- on WSL, if `reg.exe` cannot be found on the `$PATH`
+		-- (see interop.appendWindowsPath https://learn.microsoft.com/en-us/windows/wsl/wsl-config),
+		-- assume that it's in the default location
+		if M.state.system == "WSL" and not vim.fn.executable("reg.exe") then
+			local assumed_path = "/mnt/c/Windows/system32/reg.exe"
+
+			if vim.fn.filereadable(assumed_path) then
+				reg = assumed_path
+			else
+				-- `reg.exe` isn't on `$PATH` or in the default location, so throw an error
+				error([[
+          auto-dark-mode.nvim:
+          `reg.exe` is not available. To support syncing with the host system,
+          this plugin relies on `reg.exe` being on the `$PATH`.
+        ]])
+			end
+		end
+
 		M.state.query_command = {
-			"reg.exe",
+			reg,
 			"Query",
 			"HKCU\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
 			"/v",
@@ -107,7 +119,7 @@ M.init = function()
 	end
 
 	-- when on a supported unix system, and the userid is root
-	if (M.state.system == "Darwin" or M.state.system == "Linux") and getuid() == 0 then
+	if (M.state.system == "Darwin" or M.state.system == "Linux") and uv.getuid() == 0 then
 		local sudo_user = vim.env.SUDO_USER
 
 		if sudo_user ~= nil then
@@ -122,7 +134,7 @@ M.init = function()
 				auto-dark-mode.nvim:
 				Running as `root`, but `$SUDO_USER` is not set.
 				Please open an issue to add support for your system.
-				]])
+      ]])
 		end
 	end
 
diff --git a/lua/auto-dark-mode/interval.lua b/lua/auto-dark-mode/interval.lua
index e1952a6..797bf4f 100644
--- a/lua/auto-dark-mode/interval.lua
+++ b/lua/auto-dark-mode/interval.lua
@@ -7,6 +7,8 @@ local M = {
 	currently_in_dark_mode = nil,
 }
 
+local uv = vim.uv or vim.loop
+
 -- Parses the query response for each system, returning `true` if the system is
 -- in Dark mode, `false` when in Light mode.
 ---@param res string
@@ -35,8 +37,10 @@ local function parse_query_response(res)
 	return false
 end
 
+-- Executes the `set_dark_mode` and `set_light_mode` hooks when needed,
+-- otherwise it's a no-op.
 ---@param is_dark_mode boolean
-local function change_theme_if_needed(is_dark_mode)
+local function sync_theme(is_dark_mode)
 	if is_dark_mode == M.currently_in_dark_mode then
 		return
 	end
@@ -57,11 +61,17 @@ local function change_theme_if_needed(is_dark_mode)
 	end
 end
 
-M.poll_dark_mode = function()
+---@param callback? fun(is_dark_mode: boolean): nil
+M.poll_dark_mode = function(callback)
+	-- if no callback is provided, use a no-op
+	if callback == nil then
+		callback = function() end
+	end
+
 	if vim.system then
 		vim.system(M.state.query_command, { text = true }, function(data)
 			local is_dark_mode = parse_query_response(data.stdout)
-			change_theme_if_needed(is_dark_mode)
+			callback(is_dark_mode)
 		end)
 	else
 		-- Legacy implementation using `vim.fn.jobstart` instead of `vim.system`,
@@ -70,7 +80,7 @@ M.poll_dark_mode = function()
 			stdout_buffered = true,
 			on_stdout = function(_, data, _)
 				local is_dark_mode = parse_query_response(table.concat(data, "\n"))
-				change_theme_if_needed(is_dark_mode)
+				callback(is_dark_mode)
 			end,
 		})
 	end
@@ -80,17 +90,22 @@ M.start_timer = function()
 	---@type number
 	local interval = M.options.update_interval
 
-	if vim.uv.new_timer or vim.loop.new_timer then
-		M.timer = vim.uv.new_timer() or vim.loop.new_timer()
-		M.timer:start(interval, interval, M.poll_dark_mode)
+	local timer_callback = function()
+		M.poll_dark_mode(sync_theme)
+	end
+
+	-- needs to check for `vim.system` because the poll function depends on it
+	if uv and vim.system then
+		M.timer = uv.new_timer()
+		M.timer:start(interval, interval, timer_callback)
 	else
-		M.timer_id = vim.fn.timer_start(interval, M.poll_dark_mode, { ["repeat"] = -1 })
+		M.timer_id = vim.fn.timer_start(interval, timer_callback, { ["repeat"] = -1 })
 	end
 end
 
 M.stop_timer = function()
-	if vim.uv.timer_stop or vim.loop.timer_stop then
-		vim.uv.timer_stop(M.timer)
+	if uv.timer_stop then
+		uv.timer_stop(M.timer)
 	else
 		vim.fn.timer_stop(M.timer_id)
 	end
@@ -102,7 +117,7 @@ M.start = function(options, state)
 	M.options = options
 	M.state = state
 
-	M.poll_dark_mode()
+	M.poll_dark_mode(sync_theme)
 	M.start_timer()
 end